Been having an issue that´s driving me nuts .Playback ends randomly

As I said when i´m watching something the episodes or movies end randomly as if it finished. Sometimes is after 30 minutes and other after less. I´m using my personal pc as a server.

My specs are :Windows 11, RTX 4070 TI SUPER, RYZEN 7 7800X3D, 32 GB RAM, and a WD Red Plus NAS 6TB HDD.

I play my content on a CoreELEC ugoos am6b+ and both pc and ugoos are connected via LAN to my 1gb fiber optic internet.

Im doing 4k HDR playback with direct play if that´s relevant.

(Unrelated its weird but i see something like lines across the screen as if its pixelated and a lot of small dots(film grain?) even when my file is a blu ray remux. Should I make separate post for this?)

I´m paying for plex pass and its making me go crazy, dont know if both are a me and my settings issue or a plex issue.

I’m not aware that there is a native Plex client for CoreELEC.

Its on all my devices: android phone and chrome pc . Maybe I should have been more thorough on my post. Also happens on 1080p and other resolutions and sdr.

May I get some help with this issue???