The server crashed because of something radiation related causing lag. Not sure if it's related to one of the issues already posted (there seem to be some lag/radiation things mentioned but I'm not sure if it's the exact same issue or not) or not but figured I should post it here just to be safe.

https://pastebin.com/7eVEJASQ

I'm afraid this is something that I basically have no chance of outright fixing, as I think it's a mod adding some weird override for getting the metadata of one of its blocks, so instead I can add a config to just disable the block checks altogether. Here's a test build if you want to try it out; the config is called "Block Radiation Contribution" in-game, or radiation_check_blocks in the config file.

Do you have any idea of which block is causing it? We're having a tough time recreating this as it is on a server (and the crash isn't consistent and we're not exactly sure what/if the player did anything in particular) so it would need to be uploaded to curse in order to get added to the server pack but I will see if I can get the server owners to try it out anyways.

Can't tell unfortunately, as it's not been reported before and the log doesn't say. It's just happening during the routine chunk radiation cycle, while trying to get the radiation contribution of a random block in the chunk. It's getting the block metadata which is causing the trouble. How often is it happening on the server?

Sadly the server owners didn't keep track so it might've been a situation where someone placed a block and then broke it afterwards without realizing it was causing the issue. Is there a way to force the routine chunk radiation cycle so we can test things that may potentially cause it?

How about one which is a bit faster but also logs the blocks it's checking?

That could work

How fast would it be though?

I've just made it quicker by having the block checks happen in every chunk of the radiation update cycle, rather than just one of them per round. Here's the link.

Here's a version of the original test build in which I didn't forget to actually stop the checks with the config disabled :P

Honestly I have no clue where to even start and since the pack is getting remade anyways it doesn't make sense timewise to put all of the blocks one by one in a high radiation area. If the issue arises in the new pack I'll be sure to report it and hopefully have more info such as logs rather than just a crash report.

Alright, no worries, unfortuantely it was a needle-in-a-haystack type problem :P