Okay, so this glitch has been around for a LONG time but I only recently found out about it. There is a quest called 'Rise in the east' which you travel to a location called Japhet's Folly. This location is separated from Skyrim and is its own world which you cannot swim back due to invisible barriers. After completing the quest for it, I didn't go back there for a while until now which I was too late to discover this glitch. If you fast travel back there, you cannot fast travel back or swim back. Without knowing of the glitch, I accidentally saved my game when I was there and used up the auto-saves. There is no way I can leave at all. I even managed to go back on the ship that takes you there with maxed whirlwind sprint shout. But when I try to enter the ship, it just says I need a key.

When you're in this area (or outside with the ship) some of the sound has been taken away like footsteps, sword swinging, shout effects etc. The only sound you can hear are the words and grunts your character makes. If you go closer to the Japhet's Folly fort, there is a never ending explosion of arrows from boats in the distance. This is probably why some of the sound has been taken away because there is so many loud explosions going off at once.

If you enter the ice cave on the other side of the Japhet's Folly fort and then go through another door, that door you went through disappears and there is no way back because debris is blocking your path further on.

If you try swim around Japhet's Folly fort then you may notice that there is invisible water and you can look under.

These are all the glitches I know for Japhet's Folly. I really need this to be patched because I don't want to start over when I have 220+ hours on my character and I want to play the Dragonborn DLC that will be coming.