PS4 outputting wrong aspect ratio

I have several 720p DVD rips that are in 16:9 and, for some odd reason, they are stretching to fit my TV when played off of my Plex Server (Synology). I can’t see how to change this within either Plex or on the PS4 (PS4 output is set to 1080p and all other output is correct for my TV - which is a Samsung 8550 4K). Is this a known problem? Do you have any suggestions on how to troubleshoot.

This is a long standing and frustrating anamorphic video issue.