It was some weird stuff with the screen and audio issues. Probably weird software issues that were fixed with a patch.

This video isn't the best example as it cherry picks and nitpicks a bit. But there's some examples of the weird issues too.

https://youtu.be/Cb-srOfRqNc

I actually don't know how widespread the issues were or if they were overblown, but I remember seeing them pop up for the first couple of months after release. I didn't really hear about any problems after that, so I don't really know.

My assumption is that the likelihood of these issues repeating is very slim. They probably based the software and hardware off of the existing switch, so I would think it would be less buggy and more refined, but I guess we'll have to see.