Cave enderman, even with teleport blocking enabled, teleports!!!( atm 10 modpack
time on video 1.40
https://youtu.be/t2-RfAzH1q8

What mod is cave endermen from? they likely arent posting the neoforge teleport event.

That they do not...
bonsaistudi0s/Enderman-Overhaul#91

https://github.com/bonsaistudi0s/Enderman-Overhaul/blob/e3457d53f6d0bbbe1cab5ff7726f27c6b013fc6b/src/main/java/tech/alexnijjar/endermanoverhaul/common/entities/base/BaseEnderman.java#L325-L351

They are completely re-implementing the teleport method for their custom endermen.

Cave Endermen are from Enderman overhaul. I don't know enough about java to find out if they're posting the event or not, but i hope this helps!