x265 1080p HEVC files do not play correctly. They frame drop and the image is jittery.
If you are using Plex you need to disable the direct streaming option and force PLEX to transcode everything. I do not have this issue on my cheaper older TCL S425.
TCL ROKU - Please release an update to fix this issue for the R635.
No solution for you, but this happens on my Q825 as well. This is unacceptable for a TV with at that price!