v2.2.0: fixed new bomb logic causing crashes with frozen heaps

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/items/Heap.java

@@ -320,7 +320,7 @@ public class Heap implements Bundlable {
 				items.remove(item);
 				((Potion) item).shatter(pos);
 				frozen = true;
-			} else if (item instanceof Bomb){
+			} else if (item instanceof Bomb && ((Bomb) item).fuse != null){
 				frozen = frozen || ((Bomb) item).fuse.freeze();
 			}
 		}