I’ve also experienced this when using the Samsung TV Plex apps. In my experience doing what @lalala123456 suggested and disabling “Allow Direct Play” will remux the container (without transcoding the video) and usually allows for smooth playback
It’s really weird that it only affects certain files, at very specific and reproducible locations, and is resolved with an on-the-fly container remux. I really don’t know what to make of it. Especially since I’ll have no problem direct-playing a 50+mbps remux but immediately after will have problems direct-playing an unimpressive 2mbps file (which then plays back flawlessly with “Allow direct play” disabled)
I’ve also noticed the same problematic files have the same micro-buffering issues on the Xbox platform so it’s not an issue exclusive to Samsung TV’s
