diff --git a/lib/versioning/gradle/index.ts b/lib/versioning/gradle/index.ts
index 71bd6682f5be08..fa60dc22c520c1 100644
--- a/lib/versioning/gradle/index.ts
+++ b/lib/versioning/gradle/index.ts
@@ -24,7 +24,7 @@ const equals = (a: string, b: string): boolean => compare(a, b) === 0;
 const getMajor = (version: string): number | null => {
   if (isVersion(version)) {
     const tokens = tokenize(version.replace(regEx(/^v/i), ''));
-    const majorToken = tokens[0];
+    const majorToken = tokens?.[0];
     if (majorToken && majorToken.type === TokenType.Number) {
       return +majorToken.val;
     }
diff --git a/lib/workers/repository/process/lookup/bucket.ts b/lib/workers/repository/process/lookup/bucket.ts
index daa6c5f3842d98..112815aa962509 100644
--- a/lib/workers/repository/process/lookup/bucket.ts
+++ b/lib/workers/repository/process/lookup/bucket.ts
@@ -19,6 +19,10 @@ export function getBucket(
   }
   const fromMajor = versioning.getMajor(currentVersion);
   const toMajor = versioning.getMajor(newVersion);
+  // istanbul ignore if
+  if (toMajor === null) {
+    return null;
+  }
   if (fromMajor !== toMajor) {
     if (separateMultipleMajor) {
       return `major-${toMajor}`;
diff --git a/lib/workers/repository/process/lookup/index.ts b/lib/workers/repository/process/lookup/index.ts
index 93cb4189a0a908..ae5165ca9490fe 100644
--- a/lib/workers/repository/process/lookup/index.ts
+++ b/lib/workers/repository/process/lookup/index.ts
@@ -1,3 +1,4 @@
+import is from '@sindresorhus/is';
 import { mergeChildConfig } from '../../../../config';
 import type { ValidationMessage } from '../../../../config/types';
 import { CONFIG_VALIDATION } from '../../../../constants/error-messages';
@@ -238,10 +239,12 @@ export async function lookupUpdates(
           release.version,
           versioning
         );
-        if (buckets[bucket]) {
-          buckets[bucket].push(release);
-        } else {
-          buckets[bucket] = [release];
+        if (is.string(bucket)) {
+          if (buckets[bucket]) {
+            buckets[bucket].push(release);
+          } else {
+            buckets[bucket] = [release];
+          }
         }
       }
       const depResultConfig = mergeChildConfig(config, res);