diff --git a/app/src/main/java/org/thoughtcrime/securesms/groups/GroupManagerV2Impl.kt b/app/src/main/java/org/thoughtcrime/securesms/groups/GroupManagerV2Impl.kt
index c4c562da6e..bdfaa029cc 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/groups/GroupManagerV2Impl.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/groups/GroupManagerV2Impl.kt
@@ -757,6 +757,9 @@ class GroupManagerV2Impl @Inject constructor(
                     configs.groupMembers.set(member)
                 }
             }
+
+            // Remove lastHash so we can receive all the messages in the past
+            lokiAPIDatabase.clearLastMessageHashes(groupId.hexString)
         }
 
         // Delete the promotion message remotely
diff --git a/libsession/src/main/java/org/session/libsession/messaging/sending_receiving/pollers/Poller.kt b/libsession/src/main/java/org/session/libsession/messaging/sending_receiving/pollers/Poller.kt
index 41784d1caa..f2700049ff 100644
--- a/libsession/src/main/java/org/session/libsession/messaging/sending_receiving/pollers/Poller.kt
+++ b/libsession/src/main/java/org/session/libsession/messaging/sending_receiving/pollers/Poller.kt
@@ -154,7 +154,14 @@ class Poller(
         val namespace = forConfig.namespace
         val processed = if (!messages.isNullOrEmpty()) {
             SnodeAPI.updateLastMessageHashValueIfPossible(snode, userPublicKey, messages, namespace)
-            SnodeAPI.removeDuplicates(userPublicKey, messages, namespace, true).mapNotNull { rawMessageAsJSON ->
+            SnodeAPI.removeDuplicates(
+                publicKey = userPublicKey,
+                messages = messages,
+                messageHashGetter = { (it as? Map<*, *>)?.get("hash") as? String },
+                namespace = namespace,
+                updateStoredHashes = true
+            ).mapNotNull { rawMessageAsJSON ->
+                rawMessageAsJSON as Map<*, *> // removeDuplicates should have ensured this is always a map
                 val hashValue = rawMessageAsJSON["hash"] as? String ?: return@mapNotNull null
                 val b64EncodedBody = rawMessageAsJSON["data"] as? String ?: return@mapNotNull null
                 val timestamp = rawMessageAsJSON["t"] as? Long ?: SnodeAPI.nowWithOffset
diff --git a/libsession/src/main/java/org/session/libsession/snode/SnodeAPI.kt b/libsession/src/main/java/org/session/libsession/snode/SnodeAPI.kt
index 68b5f7914f..5b9860536e 100644
--- a/libsession/src/main/java/org/session/libsession/snode/SnodeAPI.kt
+++ b/libsession/src/main/java/org/session/libsession/snode/SnodeAPI.kt
@@ -12,14 +12,11 @@ import com.goterl.lazysodium.utils.Key
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.channels.SendChannel
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.selects.select
-import com.goterl.lazysodium.utils.KeyPair
-import kotlinx.coroutines.coroutineScope
 import nl.komponents.kovenant.Promise
 import nl.komponents.kovenant.all
 import nl.komponents.kovenant.functional.bind
@@ -986,7 +983,13 @@ object SnodeAPI {
     fun parseRawMessagesResponse(rawResponse: RawResponse, snode: Snode, publicKey: String, namespace: Int = 0, updateLatestHash: Boolean = true, updateStoredHashes: Boolean = true, decrypt: ((ByteArray) -> Pair<ByteArray, AccountId>?)? = null): List<Pair<SignalServiceProtos.Envelope, String?>> =
         (rawResponse["messages"] as? List<*>)?.let { messages ->
             if (updateLatestHash) updateLastMessageHashValueIfPossible(snode, publicKey, messages, namespace)
-            parseEnvelopes(removeDuplicates(publicKey, messages, namespace, updateStoredHashes), decrypt)
+            removeDuplicates(
+                publicKey = publicKey,
+                messages = parseEnvelopes(messages, decrypt),
+                messageHashGetter = { it.second },
+                namespace = namespace,
+                updateStoredHashes = updateStoredHashes
+            )
         } ?: listOf()
 
     fun updateLastMessageHashValueIfPossible(snode: Snode, publicKey: String, rawMessages: List<*>, namespace: Int) {
@@ -1005,17 +1008,35 @@ object SnodeAPI {
      * database#setReceivedMessageHashValues is only called here.
      */
     @Synchronized
-    fun removeDuplicates(publicKey: String, rawMessages: List<*>, namespace: Int, updateStoredHashes: Boolean): List<Map<*, *>> {
+    fun <M> removeDuplicates(
+        publicKey: String,
+        messages: List<M>,
+        messageHashGetter: (M) -> String?,
+        namespace: Int,
+        updateStoredHashes: Boolean
+    ): List<M> {
         val hashValues = database.getReceivedMessageHashValues(publicKey, namespace)?.toMutableSet() ?: mutableSetOf()
-        return rawMessages.filterIsInstance<Map<*, *>>().filter { rawMessage ->
-            val hash = rawMessage["hash"] as? String
-            hash ?: Log.d("Loki", "Missing hash value for message: ${rawMessage.prettifiedDescription()}.")
-            hash?.let(hashValues::add) == true
-        }.also {
-            if (updateStoredHashes && it.isNotEmpty()) {
-                database.setReceivedMessageHashValues(publicKey, hashValues, namespace)
+        return messages
+            .filter { message ->
+                val hash = messageHashGetter(message)
+                if (hash == null) {
+                    Log.d("Loki", "Missing hash value for message: ${message?.prettifiedDescription()}.")
+                    return@filter false
+                }
+
+                val isNew = hashValues.add(hash)
+
+                if (!isNew) {
+                    Log.d("Loki", "Duplicate message hash: $hash.")
+                }
+
+                isNew
+            }
+            .also {
+                if (updateStoredHashes && it.isNotEmpty()) {
+                    database.setReceivedMessageHashValues(publicKey, hashValues, namespace)
+                }
             }
-        }
     }
 
     private fun parseEnvelopes(rawMessages: List<*>, decrypt: ((ByteArray)->Pair<ByteArray, AccountId>?)?): List<Pair<SignalServiceProtos.Envelope, String?>> {