diff --git a/src/crypto/RoomList.js b/src/crypto/RoomList.js
index 5bb437fb7..eb5b469c6 100644
--- a/src/crypto/RoomList.js
+++ b/src/crypto/RoomList.js
@@ -71,6 +71,9 @@ export default class RoomList {
     }
 
     async setRoomEncryption(roomId, roomInfo) {
+        // important that this happens before calling into the store
+        // as it prevents the Crypto::setRoomEncryption for calling
+        // this twice for consecutive m.room.encryption events
         this._roomEncryption[roomId] = roomInfo;
         await this._cryptoStore.doTxn(
             'readwrite', [IndexedDBCryptoStore.STORE_ROOMS], (txn) => {
diff --git a/src/sync.js b/src/sync.js
index 4aa2d2482..d8dffe6b3 100644
--- a/src/sync.js
+++ b/src/sync.js
@@ -1085,15 +1085,16 @@ SyncApi.prototype._processSyncResponse = async function(
 
         self._processEventsForNotifs(room, timelineEvents);
 
-        async function processRoomEvent(e) {
+        function processRoomEvent(e) {
             client.emit("event", e);
             if (e.isState() && e.getType() == "m.room.encryption" && self.opts.crypto) {
-                await self.opts.crypto.onCryptoEvent(e);
+                self.opts.crypto.onCryptoEvent(e);
             }
         }
 
-        await Promise.mapSeries(stateEvents, processRoomEvent);
-        await Promise.mapSeries(timelineEvents, processRoomEvent);
+        stateEvents.forEach(processRoomEvent);
+        timelineEvents.forEach(processRoomEvent);
+
         ephemeralEvents.forEach(function(e) {
             client.emit("event", e);
         });