After installing filebeat updates on Ubuntu 14.04 servers, "service filebeat stop" isn't working immediately after upgrading. The processes filebeat-god and filebeat stay running although pid-file is correct.
A service restart end up in duplicate processes.
This at least happened when updating from 5.4.0 to 5.4.1 and 5.4.2.
It looks like the god-wrapper can't find the sub-processes being started with a prior (pre-upgrade) filebeat version and therefore won't stop them.