Thank you - got the crash and the corresponding logs - crash at 23:14:02 May 26.
This is being added to the set of diagnostics I have already passed to the development for crashes on this forum topic Ubuntu 18.04.2 LTS - Plex Server Crashes - Double free or corruption (!prev)
I am liasing with the development team to reproduce the crashes in a debug environment so that the bug can be found. it is a timing condition appears to arise sometimes at end of playback of transcoded video
