diff --git a/lib/config/types.ts b/lib/config/types.ts
index a1563324f48067..1f2ac991c4f7be 100644
--- a/lib/config/types.ts
+++ b/lib/config/types.ts
@@ -336,7 +336,7 @@ export interface PackageRule
   isVulnerabilityAlert?: boolean;
   matchFileNames?: string[];
   matchBaseBranches?: string[];
-  matchManagers?: string | string[];
+  matchManagers?: string[];
   matchDatasources?: string[];
   matchDepTypes?: string[];
   matchDepNames?: string[];
diff --git a/lib/config/validation.spec.ts b/lib/config/validation.spec.ts
index c2b24197c07d30..37b19ebe5ca5b9 100644
--- a/lib/config/validation.spec.ts
+++ b/lib/config/validation.spec.ts
@@ -224,7 +224,7 @@ describe('config/validation', () => {
         ],
       };
       const { warnings, errors } = await configValidation.validateConfig(
-        config
+        config as any
       );
       expect(warnings).toHaveLength(0);
       expect(errors).toHaveLength(2);