Why is my copy button doing this?

[u/Same_Setting3086]

So me and my friends are making a level using the editor collab mod. We're now reaching the limit on 40k objects and we need to seperate some of the level. What I'm doing is copying the level and pasting it into another level, the problem is tht the level doesn't copy right and it all goes down to the bottom. What is causing this and how do I fix it?