diff --git a/src/main/java/net/openhft/chronicle/hash/serialization/internal/BasicCopyingMetaBytesInterop.java b/src/main/java/net/openhft/chronicle/hash/serialization/internal/BasicCopyingMetaBytesInterop.java
index 250cd18f8..450d067a9 100644
--- a/src/main/java/net/openhft/chronicle/hash/serialization/internal/BasicCopyingMetaBytesInterop.java
+++ b/src/main/java/net/openhft/chronicle/hash/serialization/internal/BasicCopyingMetaBytesInterop.java
@@ -52,7 +52,7 @@ public abstract class BasicCopyingMetaBytesInterop<E, W> implements MetaBytesInt
 
     @Override
     public boolean startsWith(W writer, Bytes bytes, E e) {
-        return bytes.startsWith(buffer.buffer);
+        return BytesBytesInterop.INSTANCE.startsWith(bytes, buffer.buffer);
     }
 
     @Override
diff --git a/src/main/java/net/openhft/chronicle/map/ReplicatedChronicleMap.java b/src/main/java/net/openhft/chronicle/map/ReplicatedChronicleMap.java
index 76872a084..c31e87159 100644
--- a/src/main/java/net/openhft/chronicle/map/ReplicatedChronicleMap.java
+++ b/src/main/java/net/openhft/chronicle/map/ReplicatedChronicleMap.java
@@ -929,12 +929,12 @@ final class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? supe
                         throw defaultValueOrPrepareBytesShouldBeSpecified();
                     }
 
-                    final long size = metaElemWriter.size(elemWriter, elem);
+                    final long elemSize = metaElemWriter.size(elemWriter, elem);
 
                     putValue(pos, entry, valueSizePos,
                             entryEndAddr, isDeleted,
                             segmentState,
-                            metaElemWriter, elemWriter, elem, size,
+                            metaElemWriter, elemWriter, elem, elemSize,
                             hashLookup, sizeOfEverythingBeforeValue);
                     pos = segmentState.pos;
 
@@ -943,6 +943,7 @@ final class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? supe
 
                     entry.position(valueSizePos);
                     long valueSize = readValueSize(entry);
+                    assert valueSize == elemSize;
                     long valuePos = entry.position();
                     RV v = readValue.readValue(copies, entry, usingValue, valueSize);
 
@@ -1154,9 +1155,9 @@ final class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? supe
                     }
 
                     // put callbacks
+                    boolean hasValueChanged = updateResult != UpdateResult.UNCHANGED;
                     onPutMaybeRemote(segmentState.pos, false);
                     if (bytesEventListener != null) {
-                        boolean hasValueChanged = updateResult != UpdateResult.UNCHANGED;
                         bytesEventListener.onPut(
                                 entry, 0L, metaDataBytes, valueSizePos, false, false,
                                 hasValueChanged,
@@ -1164,7 +1165,6 @@ final class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? supe
                                 timeStamp, replacedTimestamp);
                     }
                     if (eventListener != null) {
-                        boolean hasValueChanged = updateResult != UpdateResult.UNCHANGED;
                         eventListener.onPut(toKey.toInstance(copies, key, keySize),
                                 toValue.toInstance(copies, value, valueSize), null, false,
                                 isDeleted, hasValueChanged, identifier, replacedIdentifier,
@@ -1207,7 +1207,8 @@ final class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? supe
                     long replacedTimestamp = 0;
 
                     bytesEventListener.onPut(entry, 0L, metaDataBytes,
-                            segmentState.valueSizePos, true, false, true, identifier, replacedIdentifier, timeStamp, replacedTimestamp);
+                            segmentState.valueSizePos, true, false, true, identifier,
+                            replacedIdentifier, timeStamp, replacedTimestamp);
                 }
                 if (eventListener != null) {
                     byte replacedIdentifier = 0;
@@ -1335,7 +1336,8 @@ final class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? supe
                 byte replacedIdentifier = 0;
                 long replacedTimestamp = 0;
                 bytesEventListener.onPut(entry, 0L, metaDataBytes,
-                        segmentState.valueSizePos, true, remote, true, identifier, replacedIdentifier, timestamp,
+                        segmentState.valueSizePos, true, remote, true, identifier,
+                        replacedIdentifier, timestamp,
                         replacedTimestamp);
             }
             if (eventListener != null) {
diff --git a/src/main/java/net/openhft/chronicle/map/VanillaChronicleMap.java b/src/main/java/net/openhft/chronicle/map/VanillaChronicleMap.java
index a879ccdf8..cb4ad80c7 100755
--- a/src/main/java/net/openhft/chronicle/map/VanillaChronicleMap.java
+++ b/src/main/java/net/openhft/chronicle/map/VanillaChronicleMap.java
@@ -2199,8 +2199,6 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? super KI>,
                     } else {
                         long valueAddr = entry.positionAddr();
                         long entryEndAddr = valueAddr + prevValueSize;
-                        hasValueChanged = prevValueSize != valueSize ||
-                                !metaValueInterop.startsWith(valueInterop, entry, value);
 
                         // putValue may relocate entry and change offset
                         putValue(pos, entry, valueSizePos, entryEndAddr, false, segmentState,
@@ -2211,6 +2209,7 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? super KI>,
                     }
 
                     // put callbacks
+                    boolean hasValueChanged = updateResult != UpdateResult.UNCHANGED;
                     onPutMaybeRemote(segmentState.pos, false);
                     if (bytesEventListener != null)
                         bytesEventListener.onPut(entry, 0L, metaDataBytes, valueSizePos, false,
@@ -2219,7 +2218,6 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? super KI>,
                                 segmentState.timestamp, 0
                         );
                     if (eventListener != null) {
-
                         eventListener.onPut(toKey.toInstance(copies, key, keySize),
                                 toValue.toInstance(copies, value, valueSize), null, false,
                                 false, hasValueChanged,
@@ -2323,29 +2321,19 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? super KI>,
                 }
             }
 
-
             // key is not found
             VBI valueInterop = getValueInterops.getValueInterop(copies);
             MVBI metaValueInterop =
                     getValueInterops.getMetaValueInterop(copies, valueInterop, value);
 
-
             long valueSize = putEntry(segmentState, metaKeyInterop, keyInterop, key, keySize,
                     metaValueInterop, valueInterop, value, entry, false);
 
-
-            boolean hasValueChanged = false;
-            if (eventListener != null || bytesEventListener != null) {
-                // todo roman to check this
-                hasValueChanged =
-                        !metaValueInterop.startsWith(valueInterop, entry, value);
-            }
-
             // put callbacks
             onPut(this, segmentState.pos);
             if (bytesEventListener != null)
                 bytesEventListener.onPut(entry, 0L, metaDataBytes,
-                        segmentState.valueSizePos, true, false, hasValueChanged,
+                        segmentState.valueSizePos, true, false, true,
                         segmentState.identifier, (byte) 0, segmentState.timestamp, 0);
             if (eventListener != null)
                 eventListener.onPut(toKey.toInstance(copies, key, keySize),
@@ -2411,10 +2399,7 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? super KI>,
             // put callbacks
             onPutMaybeRemote(segmentState.pos, remote);
             if (bytesEventListener != null)
-                bytesEventListener.onPut(entry, 0L, metaDataBytes, valueSizePos, false, remote,
-                        hasValueChanged,
-                        segmentState.identifier, replacedIdentifier,
-                        segmentState.timestamp, replacedTimestamp);
+                bytesEventListener.onPut(entry, 0L, metaDataBytes, valueSizePos, false, remote, hasValueChanged);
             if (eventListener != null) {
                 eventListener.onPut(toKey.toInstance(copies, key, keySize),
                         toValue.toInstance(copies, value, valueSize), prevValueInstance, remote,
@@ -2660,9 +2645,7 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? super KI>,
             // remove callbacks
             onRemoveMaybeRemote(pos, remote);
             if (bytesEventListener != null)
-                bytesEventListener.onRemove(entry, 0L, metaDataBytes, valueSizePos, remote,
-                        segmentState.identifier, replacedIdentifier,
-                        segmentState.timestamp, replacedTimestamp);
+                bytesEventListener.onRemove(entry, 0L, metaDataBytes, valueSizePos, remote);
             if (eventListener != null) {
                 V removedValueForEventListener =
                         toValue.toInstance(copies, removedValue, valueSize);
@@ -2817,10 +2800,7 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? super KI>,
             onPut(this, segmentState.pos);
             if (bytesEventListener != null) {
                 long keyPos = metaDataBytes;
-                bytesEventListener.onPut(entry, 0L, keyPos, segmentState.valueSizePos, true,
-                        false, hasValueChanged,
-                        segmentState.identifier, replacedIdentifier,
-                        segmentState.timestamp, replacedTimestamp);
+                bytesEventListener.onPut(entry, 0L, keyPos, segmentState.valueSizePos, true, false, hasValueChanged);
             }
             if (eventListener != null)
                 eventListener.onPut(toKey.toInstance(copies, key, keySize),