I can't replicate this perfectly - while I can duplicate the campfire, I can't crash the game or delete the items.

It could be some other mods we had in the modpack. I can test myself at somepoint if you want. I wondered if "torch god tweaks" was the culprit since it changes how regular wood campfires work.

All we need to fix issues is replication steps, if we can replicate we can fix it. So whatever you can get that helps replicate is helpful.

Sorry, forgot to write back. I was also unable to recreate this, however the way I tested it was on a singleplayer world, not a multiplayer world (where this happened when I originally made the discussion) so this might just be one of those awesome tmod moments. When I tested it on the singleplayer world I booted up I was using the exact same modpack I was having issues with before. If you want/need anymore testing feel free to let me know I am happy to help.

"Awesome tMod moments" don't tend to happen all that often realistically. Usually, it's on the mod for having bad multiplayer support. Testing on singleplayer is completely different, multiplayer is a massive change for almost everything in the game. So if you can't replicate it in singleplayer, that's normal.