diff --git a/lib/datasource/docker.js b/lib/datasource/docker.js
index c2c094284da3f64bc10b072c8fb52dd542e0b355..38bcc795427fe8fa58f72e1115bd88acdca176db 100644
--- a/lib/datasource/docker.js
+++ b/lib/datasource/docker.js
@@ -302,11 +302,13 @@ async function getPkgReleases(purl, config = {}) {
   if (!tags) {
     return null;
   }
-  const releases = tags
+  const sortedTags = tags
     .filter(tag => !suffix || tag.endsWith(`-${suffix}`))
     .map(tag => (suffix ? tag.replace(new RegExp(`-${suffix}$`), '') : tag))
     .filter(isVersion)
-    .sort(sortVersions)
-    .map(version => ({ version }));
-  return { releases };
+    .sort(sortVersions);
+
+  const releases = sortedTags.map(version => ({ version }));
+  const ret = { releases };
+  return ret;
 }