yes exactly the same issue, i get this on Google Chromecast 4k and Sony TVs (all of them it seems)
the same content on LG and Samsung TVs and using Windows is 100% fine never a skip
What i found is have a look at the full frame rate using VLC or something 23.976 is truncated by plex.. resolution dosnt make a difference.. just the fps
Good files are 23.976024
Bad files are 23.976216
I only see this in movies, most TV shows are MKV format which dosnt seem effected by this bug
my examples from vlc
