diff --git a/lib/workers/package-file/index.js b/lib/workers/package-file/index.js
index 8d0280823b3687c843342af3819725c1907e4ddb..c0c570e7cfc978263fabc4bb0b675c5c62c783b2 100644
--- a/lib/workers/package-file/index.js
+++ b/lib/workers/package-file/index.js
@@ -92,7 +92,7 @@ async function renovatePackageFile(packageFileConfig) {
   const depTypeConfigs = depTypes.map(depType => {
     const depTypeConfig = configParser.mergeChildConfig(
       config,
-      config[depType]
+      Object.assign({}, config[depType])
     );
     depTypeConfig.depType = depType;
     depTypeConfig.logger = logger.child({