Initially reported here: DimensionalDevelopment/VanillaFix#225, DimensionalDevelopment/VanillaFix#309

However, this issue seems to be caused by Surge, not VanillaFix. I was able to reproduce the aforementioned issues in a test instance with just Surge and Extra Utilities 2 installed.

It seems that whatever method Surge uses to store bounding boxes is incompatible with the method Extra Utilities 2 uses to respawn mobs stored in golden lassos, resulting in a desync where the mob spawns in the new position client-side, but is really in the old position server-side. When the mob takes damage, the client realizes the new location and the mob visually teleports to its old location.

The lasso implementation is here: https://github.com/rwtema/Extra-Utilities-2-Source/blob/9e478a1f48b559c404747c663cbb29bd8acf93d9/1.10.2/src/main/java/com/rwtema/extrautils2/items/ItemGoldenLasso.java

Workaround: disabling fixMobsWallGlitching in config/surge.cfg allows you to work around this issue, but it will reintroduce MC-2025.

Hello, you can read more about this issue here. There are known fixes however this mod is currently not being updated.