I have all UNU packs in the mods folder of a 1.12.2 server. currently using MTS version 19.13.0. Packs like GAP load successfully but packs like UNU Civilian Pack doesn't seem to work properly. When a car is spawn through creative means it disconnects the player who spawned it.

MTS: 19.13.0
UNU Packs: 3.5.0
UNU Civilian Pack: 3.5.0

You'll have to get with UNU on this one.

Closing, as UNU just dropped the V4 update, and this should be taken care of by that update.