I use gerrit with Google Play Android Publisher Plugin the way it described in plugin tutorial on the plugin page. .apk is signed and if I upload it via google play gui it
I have a same issue, but I solve with change the Google oAuth plugin (dependency for Google Play publish plugin) from v0.4 to v0.3.
You can downgrade by install manualy.
Download here: https://updates.jenkins-ci.org/download/plugins/google-oauth-plugin/ (this is a *.hpi file)
Manage Jenkins > Manage Plugins > Advanced > Upload plugin
It works for me.