diff --git a/src/models/room.js b/src/models/room.js
index 94115ef45..acac0ef4d 100644
--- a/src/models/room.js
+++ b/src/models/room.js
@@ -1141,7 +1141,10 @@ Room.prototype.recalculate = function() {
         "m.room.member", this.myUserId,
     );
     if (membershipEvent && membershipEvent.getContent().membership === "invite") {
-        const strippedStateEvents = membershipEvent.event.invite_room_state || [];
+        const strippedStateEvents = (
+            membershipEvent.event.unsigned ?
+            membershipEvent.event.unsigned.invite_room_state :
+            []) || [];
         utils.forEach(strippedStateEvents, function(strippedEvent) {
             const existingEvent = self.currentState.getStateEvents(
                 strippedEvent.type, strippedEvent.state_key,