diff --git a/src/logic/utils/general-utils.ts b/src/logic/utils/general-utils.ts
index 13f6885..92313ff 100644
--- a/src/logic/utils/general-utils.ts
+++ b/src/logic/utils/general-utils.ts
@@ -2,5 +2,6 @@
 export function findLastIndex<T>(array: T[], callback: (v: T) => boolean): number
 {
     let arr2 = array.slice().reverse();
-    return arr2.length - arr2.findIndex(callback);
+    let result = arr2.length - arr2.findIndex(callback);
+    return result == -1 ? -1 : result - 1;
 }