diff --git a/src/stores/room-list/RoomListStore.ts b/src/stores/room-list/RoomListStore.ts
index 77beeb4ba1..58eb6ed317 100644
--- a/src/stores/room-list/RoomListStore.ts
+++ b/src/stores/room-list/RoomListStore.ts
@@ -668,7 +668,7 @@ export class RoomListStoreClass extends AsyncStoreWithClient<IState> {
      * and thus might not cause an update to the store immediately.
      * @param {IFilterCondition} filter The filter condition to add.
      */
-    public addFilter(filter: IFilterCondition): void {
+    public async addFilter(filter: IFilterCondition): Promise<void> {
         if (SettingsStore.getValue("advancedRoomListLogging")) {
             // TODO: Remove debug: https://github.com/vector-im/element-web/issues/14602
             console.log("Adding filter condition:", filter);
@@ -680,12 +680,14 @@ export class RoomListStoreClass extends AsyncStoreWithClient<IState> {
             promise = this.recalculatePrefiltering();
         } else {
             this.filterConditions.push(filter);
-            if (this.algorithm) {
-                this.algorithm.addFilterCondition(filter);
-            }
             // Runtime filters with spaces disable prefiltering for the search all spaces effect
             if (SettingsStore.getValue("feature_spaces")) {
-                promise = this.recalculatePrefiltering();
+                // this has to be awaited so that `setKnownRooms` is called in time for the `addFilterCondition` below
+                // this way the runtime filters are only evaluated on one dataset and not both.
+                await this.recalculatePrefiltering();
+            }
+            if (this.algorithm) {
+                this.algorithm.addFilterCondition(filter);
             }
         }
         promise.then(() => this.updateFn.trigger());
diff --git a/src/stores/room-list/algorithms/Algorithm.ts b/src/stores/room-list/algorithms/Algorithm.ts
index 83ee803115..f3f0b178dd 100644
--- a/src/stores/room-list/algorithms/Algorithm.ts
+++ b/src/stores/room-list/algorithms/Algorithm.ts
@@ -577,9 +577,8 @@ export class Algorithm extends EventEmitter {
 
         await this.generateFreshTags(newTags);
 
-        this.cachedRooms = newTags;
+        this.cachedRooms = newTags; // this recalculates the filtered rooms for us
         this.updateTagsFromCache();
-        this.recalculateFilteredRooms();
 
         // Now that we've finished generation, we need to update the sticky room to what
         // it was. It's entirely possible that it changed lists though, so if it did then