Possible Fixes

Yes

Modpack Version

2.20

What happened?

On the most upper layer of my base there are beacons and empty space above them (but there is also an base roof on y319)
After updating from 2.13, and playing for some time, I checked the upper floor and there was blood spots EVERYWHERE, also I picked up a lot of loot like some armor, weapons, and gunpowder
Also when I was flying, one of the creepers spawned and played creeper "activation" sound, but then fell and died
And also they are completely invisible, they are not visible on the map too
And when they die, the server console shows this
ChristmasCreeperEntity died

latest.log

https://gist.github.com/DADA30000/0b63d6db22a209e30a48a10afbefd3b8

Developer reports

No response

if screenshots are needed, you can find them here https://www.reddit.com/r/allthemods/comments/1hw6bhw/my_base_is_haunted_with_christmas_creepers/

I forgot to remove old mods when I was updating the server, deleting them solved this