version 1.12.3.4973 on Synology NAS DS918+ shows cut-short

Version 1.12.3.4973 running on a Synology DS918+ running Disk Station DSM 6.1.6-15266 Update 1 - Client Samsung Smart TVs (different models) - playback stopping about 1:30 before show ends. Show showing as watched.

Any suggestions?

(I did review earlier forum posts of this happening around Nov 2017 - but these seemed to be fixed with subsequent releases)