I am very sorry for bringing this issue up. I wouldn't have, however the team working on RHS has said (A while ago) they don't intend to make another update (Working on Reforger).
This vehicle is (was?) used as the main transport vehicle in RHS KOTH (One of the bigger PVP missions still running), but is now essentially useless because the instant a living being sees you you're disabled.
It's a frustrating issue that would be amazing to have fixed, I'm sorry I can't tell you what specifically was changed that caused it, if there's any way to make an exception to whatever is causing it just for the one class, us KOTH players would be forever greatful! :)
Vehicle classname if needed - **RHS_MELB_MH6M**
Side note; C4G (Big group running many KOTH servers) has been trying to get in touch with the RHS team to ask them to mod the config / attempt to repair the caused issue seemingly with no luck. They will continue trying, but no guarantees there.