Fabric server 1.16.5 don`t start with Chunky.
2021-02-07-5.log

It's working for me, and I don't see anything in your log that indicates an error with Chunky.

Is this a new problem? Did it work with previous versions? More information would be appreciated.

With 1.2.8 server don`t start too
2021-02-07-6.log

And without Chunky server starts successfully.
A visually similar error was due to a conflict between worldedit and carpet.

UPD: When i deleted LuckPerms mod server start with Chunky. It's confict with LuckPerms (v5.2.104).
I don't know on which side this conflict can be resolved.

Closing this because I'm fairly certain at this point that it's a LuckPerms issue. I've heard from other people now that this happens commonly with other mods too. For now, a workaround is just to run Chunky without LuckPerms, and then add LuckPerms only after you are done pre-generating.

@Nidre I spoke with Luck and he managed to figure out what the problem was. Should be fixed in the latest version of LuckPerms and Chunky, as it happened to be a bug on both sides. If anyone continues to have this issue, I recommend updating either to the latest version.

You can find the latest version of LuckPerms here and Chunky here.