I play a realm with my nephew. We are both in the over world. we have no issues until one of us tries to enter a nether portal, the one who enters gets stuck at a "Building terrain" screen. The other player can continue moving around but can't interact with the world. we both have to force quit the software. Upon restarting, neither of us can join the realm. To restore functionality i have to restore a backup from before we attempted to enter the portal. I have done some experimenting.
The issue occurs in downloaded copies of the realm
the issue occurs with new portals, and breaking and re-igniting existing portals
the issue happens on various platforms
I was able to travel a ways from our base, create a portal, enter the nether and return to the overworld repeatedly, however upon traveling to our nether base and attempting to portal back to the overworld, the game locked up.
the issue only happens in one of the 3 worlds in the realm
the issue happens in even the oldest backups, which unfortunately aren't very old at this point
downloading a copy, and uploading it to replace the world in the realm, made no difference.
Comments


https://1drv.ms/u/s!AtRv7_mE_M15ga55JqCwy1s0nRgGRg?e=dXxzB9
Does that work?

Yes, thank you.

Hi, I entered your world and entered Nether around 1000 blocks from spawn in the overworld. I teleported to 0, 0 in nether on spectator mode and noticed that there is over 41 thousand monsters spawned. Can it be connected to the farm near spawn?
I think there is not much we can do in terms of the report, but you can try to resolve your issue by /kill @e the mobs, previously entering the world like I did. Just make sure to be on spectator mode when in the spawn region of the nether, entities load slower this way and the lag can be bearable.
Edit: You can also just change the world difficulty to peaceful since they are just accumulated monsters, they should be gone once the difficulty is changed. Let me know if it worked.

I don't know how to do spectator mode in bedrock. I also don't know how to tell how many mobs exist. I switched the realm to peaceful and headed towards 0,0 in the nether. however, the game became unresponsive before i got there. I tried again and was able to detect the specific place issues start. I tried again but had the same results. I'm hoping to avoid turning on cheats in the realm b/c that deactivates achievement. I downloaded the realm and put it in creative. then issues the /kill @e. this ground the game to a halt, but even after the game became responsive again, i was not able to interact with anything or open my inventory.
I am not aware of any farms that could cause this, but i'm not up on all the farms and how they function. To my knowledge we don't have any farms in the nether. we do have an overworld gold farm that operates by activating and deactivating portals, but my understanding is that those portals aren't linked in the nether.

I would say that removing a decent amount of the 41 000 monsters spawned would aid this as the simulation is trying to build all which leads to the lag and eventual crash. The simulation was not meant to handle this and if you remove some monsters gameplay will go back to normal.
You can enter spectator mode by entering /gamemode @s spectator to chat. This only can be done with cheats of course.
This is a bug report site not a support site, so I cannot walk you through the problem like the support would. I would suggest that you delete the monsters and try to prevent building up more of them in the nether by turning your nether portals off when you don't use them, especially the gold farm.
Closing.
Could you attach a copy of the world? If the world is too large to attach, you can upload it to a site like OneDrive or Dropbox and share the download link.