had the same, also with h264 and h265. Did test different SD cards (which was suggested in here) und tested different buffering settings. None of it provided a solution. No matter if I play vom SD, USB, DLNA, SMB.
I think buffering is the problem, because the grey buffering bar is jumping like a maniac, while it is very calm in other hardware/releases. Perhaps you can check that behavior on your device.