Hi. I use Pi4 with 4G RAM.
It crashes (start to reboot) in the middle of the 4k movie at the certain moment.
After reboot, if I try to watch the same movie, it shows exactly the same moment and starts repeating this moment (1 second of it) in a endless loop.
When I watch he same movie on a PC or via my smartTV, it works well.
I repeated it several times. It crashaes again and again.