I’ve had a few issues with 50GB discs. More so just the “mount” or whatever you call it when the player is trying to figure out what type of media (dvd/cd/bd) you have put in. Sometimes it takes up to a minute or so to make that determination. Sometimes it fails saying it isn’t a supported media. Sometime it just starts up aok.
It might be my player as well, as its an older (6 yrs?) Panasonic. Or it could be trying to do some network stuff.
In any event, after a successful load I haven’t seen any other playback issues with the 50GB images.
I burned to Optical Quantum 50/25GB BD’s and 8.5/4.7GB DVD at a relatively low speed.