BUG #14979: PostGres does not start at reboot

The following bug has been logged on the website:

Bug reference: 14979
Logged by: Darren Baber
Email address: dbaber(at)rm(dot)com
PostgreSQL version: 9.3.5
Operating system: Windows Server (standard) 2012R2 & 2016
Description:

The issue is described here:
http://www.dbforums.com/showthread.php?1707155-PostgreSQL(pg_ctl)-service-failed-to-start-but-postgres-exe-running.
We see a postmaster.pid created, some running PostGres.exe instances - BUT
the "RMConnect PostgreSQL Database Server" service is stopped (this is our
name for the key PG service running on the server). We have to kill the
running PostGres.exe instances and then this service will start.
We suspect that the Postmaster.pid file is NOT being removed cleanly at
reboot - and thus at the next reboot the file is present and the start-up of
PostGres sees this file and enters the error state.
Note: We have 9.3.5 rolled out to hundreds of customer sites and this is
only happening at a small handful right now. We cannot find a common cause
amongst them (there are different AV solutions in place - with restrictions
in place for the PostGres install folders).