Zend certified PHP/Magento developer

Why can my device through PLEX only play one of these two 4K files?

I have two 4K .mkvs consisting of both video and audio tracks – my device seems to be able to play 4K content just fine for a movie, but won’t playback upscaled 120 fps content. Both videos are x265 and the main thing I seem to be able to pinpoint would be the fps causing trouble or perhaps the encoder being v1.4.4 vs the movie one being v.1.4.5. Could anybody help me out from the ffprobe info?

Movie

Upscaled content