diff --git a/src/core/game/GameMap.ts b/src/core/game/GameMap.ts
index 65c6b5bae..d450905c3 100644
--- a/src/core/game/GameMap.ts
+++ b/src/core/game/GameMap.ts
@@ -277,7 +277,11 @@ export class GameMapImpl implements GameMap {
   ): Set<TileRef> {
     const seen = new Set<TileRef>();
     const q: TileRef[] = [];
-    q.push(tile);
+    if (filter(this, tile)) {
+      seen.add(tile);
+      q.push(tile);
+    }
+
     while (q.length > 0) {
       const curr = q.pop();
       for (const n of this.neighbors(curr)) {