Just to help out dev here, there are number of tickets reporting same issue.
Related tickets:
BDS-10926 (steps to reproduce and world attached)
MCPE-98133 (One of the comment suggests issue might be with libc library version)
Similar issue resolved in the past:
Come on devs, fix it, we did the leg work for you 😉
I'm getting the same error on Ubuntu 20 server. I moved the world to Windows 10 server and it's working without problems (just a workaround if anyone interested).
I don't want to use win 10 just for that. Please fix it.
Sean, I think the suggestion about libc version was that you need to downgrade it, as issue started after updating the server.
Trying on not up-to-date Ubuntu 18 or similar could be a good test.