diff --git a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/helper/RoomEntityHelper.kt b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/helper/RoomEntityHelper.kt
index ada07479..cec664c2 100644
--- a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/helper/RoomEntityHelper.kt
+++ b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/helper/RoomEntityHelper.kt
@@ -21,6 +21,7 @@ import im.vector.matrix.android.internal.database.mapper.toEntity
 import im.vector.matrix.android.internal.database.mapper.updateWith
 import im.vector.matrix.android.internal.database.model.ChunkEntity
 import im.vector.matrix.android.internal.database.model.RoomEntity
+import im.vector.matrix.android.internal.database.query.fastContains
 
 
 internal fun RoomEntity.deleteOnCascade(chunkEntity: ChunkEntity) {
@@ -37,16 +38,17 @@ internal fun RoomEntity.addOrUpdate(chunkEntity: ChunkEntity) {
 
 internal fun RoomEntity.addStateEvents(stateEvents: List<Event>,
                                        stateIndex: Int = Int.MIN_VALUE,
+                                       filterDuplicates: Boolean = false,
                                        isUnlinked: Boolean = false) {
     if (!isManaged) {
         throw IllegalStateException("Chunk entity should be managed to use fast contains")
     }
     stateEvents.forEach { event ->
-        if (event.eventId == null) {
+        if (event.eventId == null || (filterDuplicates && fastContains(event.eventId))) {
             return@forEach
         }
         val eventEntity = event.toEntity(roomId)
         eventEntity.updateWith(stateIndex, isUnlinked)
         untimelinedStateEvents.add(eventEntity)
     }
-}
\ No newline at end of file
+}
diff --git a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/query/RoomEntityQueries.kt b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/query/RoomEntityQueries.kt
index 17c9246e..211421ef 100644
--- a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/query/RoomEntityQueries.kt
+++ b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/query/RoomEntityQueries.kt
@@ -17,6 +17,7 @@
 package im.vector.matrix.android.internal.database.query
 
 import im.vector.matrix.android.api.session.room.model.MyMembership
+import im.vector.matrix.android.internal.database.model.EventEntity
 import im.vector.matrix.android.internal.database.model.RoomEntity
 import im.vector.matrix.android.internal.database.model.RoomEntityFields
 import io.realm.Realm
@@ -34,3 +35,7 @@ internal fun RoomEntity.Companion.where(realm: Realm, membership: MyMembership?
     }
     return query
 }
+
+internal fun RoomEntity.fastContains(eventId: String): Boolean {
+    return EventEntity.where(realm, eventId = eventId).findFirst() != null
+}
diff --git a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/sync/RoomSyncHandler.kt b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/sync/RoomSyncHandler.kt
index 7cd703c7..4e699925 100644
--- a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/sync/RoomSyncHandler.kt
+++ b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/sync/RoomSyncHandler.kt
@@ -92,7 +92,7 @@ internal class RoomSyncHandler(private val monarchy: Monarchy,
 
         if (roomSync.state != null && roomSync.state.events.isNotEmpty()) {
             val untimelinedStateIndex = if (isInitialSync) Int.MIN_VALUE else stateIndexOffset
-            roomEntity.addStateEvents(roomSync.state.events, stateIndex = untimelinedStateIndex)
+            roomEntity.addStateEvents(roomSync.state.events, filterDuplicates = true, stateIndex = untimelinedStateIndex)
         }
 
         if (roomSync.timeline != null && roomSync.timeline.events.isNotEmpty()) {