Server Log: https://pastebin.com/RVXNTjwN

Updated our server from 1.16.5 to 1.18.1 recently and we noticed a combination of a memory leak and an server overload crash when the server gets spammed with messages such as:

30.12 16:37:47 [Server] Server thread/ERROR Unknown structure start: quark:big_dungeon
30.12 16:37:47 [Server] Server thread/WARN Found reference to unknown structure 'quark:big_dungeon' in chunk [1040, -22], discarding

I will point out that once the task has been done for the area the message won't pop up again (leaving a gaping whole in the area the dungeon would be) but RAM usage on the server does not go down.

EDIT: Managed to catch the log for when the server goes down, here you go! https://pastebin.com/atRbvCHn

Unfortunately updating from 1.16 to 1.18 is not supported. Too many changes were made for that to work.