[brazen1]

I'd bet a sbs.mkv via USB directly into the display using its internal player would switch 1st time every time.  I think by the time the file is run through various software players, the display doesn't have it raw enough to know what to do even though the header metadata is defined.  There was a point in time when external software had to evoke 3D since the panel failed to do it automatically.  Those days are gone.  Displays evolved and/or software understands how to handoff mkv butcher jobs better I suppose.  This is all just another reason I prefer untouched rips in there native format.

https://forum.kodi.tv/showthread.php?tid...id=1623427