It's on a Dawncraft dedicated server running this mod.
We play along normally and when phantoms appeared and everything got broken.

3 phantom spawned and one of my friend was grabbed.
Others were shooting on near entities, nearby there was a cat who made them flee sometimes like normal.
After a while the server kept freezing, trying to process something it couldn't.
Some research later, we found out that the Phantom Shockwave was fired so it ended up reaching Y 20000000, being the height limit of Minecraft (Can't even use /tp above that limit)

You can reproduce the bug with this command.
/summon revamped_phantoms:shockwave ~ ~3 ~ {Motion:[0.0,1.0,360.0]}
it take a second before lagging.
You can solve the problem with this following command
/kill @e[type=revamped_phantoms:shockwave] or /kill @e

Server keep freezing trying to process each tick from the height the shockwave reached.

Here is a picture of the chunk with the entity attack with y 20000000
https://i.imgur.com/ZZoEera.png

• Forge 40.2.1
• v0.2.3

https://github.com/SettingDust/dawncraft-fixes/blob/main/mod/src/main/java/io/github/settingdust/dawncraftfixes/mixin/revampedphantoms/MixinShockwave.java

https://legacy.curseforge.com/minecraft/mc-mods/mod-compat-fixes/files

fixed with this in 1182

This should be fixed in the 1.20.4 version; the 1.18 version is on life support, so I can't guarantee that I'll get to a fix for that version anytime soon.

What I have in 1.20.4 is a very similar fix; the issue is mostly that I don't want to re-configure all the stuff to release a 1.18.2 version when I have not touched that version in a very long time, but if I happen to be doing so for another reason I'll bundle a fix for this in.

Hmm. I thought I had some lifetime stuff set up to avoid this, but apparently I either didn't or it doesn't work. I'll poke at it at some point; this whole mod will get rewritten sometime soon anyways, but I'll try to get a fix in before then.