diff --git a/lib/manager/npm/post-update/index.js b/lib/manager/npm/post-update/index.js
index 18dded9effa1ca99ea951d652dc38af4ee34edfb..ed68d0c22ded82c69c6566482510e6a05dd83883 100644
--- a/lib/manager/npm/post-update/index.js
+++ b/lib/manager/npm/post-update/index.js
@@ -452,6 +452,9 @@ async function getAdditionalFiles(config, packageFiles) {
     } else {
       lockFile = config.yarnLock || 'yarn.lock';
     }
+    if (!config.lernaClient) {
+      logger.debug({ config }, 'lernaClient debug');
+    }
     logger.debug(
       { lernaClient: config.lernaClient, lockFile },
       'Generating lock files using lerna'