It's happed to me a couple of times already, I go through the nether portal and it outs me in a completely different nether portal very far way and it could go from a thought broks away to almost 25 thousands blocks away

When you go through the portal itself isn't visible but if you leave the game and come back the portal appears, you can go through but you'll be in the middle of no where, you options are go back in the nether and find your other portal which can be pretty difficult when you're very far away or go back to the overworld and walk your way home now for people like me that are waiting for the new generation to come that's a lot of chunks to load on th way back otherwise you could just die you'll spawn at your bed if you did set a spawn point. It's happened twice now first time I just killed myself so I could go back to my house but the before it happened a second time I made a copy of the world just in case it happened and what do you know, I don't wanna be 30k blocks away from my base just because I wanted to go to the nether for a sec

Not quite sure but It might be something to do with autosave

The first two or tree times I noticed it happened while it was autosaving then again the game saves every minute but the last time I waited for it to end and I still got teleported I'm scared to even think of the end if I go there