Not entirely sure if this is bugged but he has only 700 mass on his Razordon mount and almost deals no dmg in melee , i do play with a variety of mods. But many mods i am using that use custom models etc. are having this problem after the last few patches.
(also tested him standalone)

I believe he is missing collision dmg or smth, if he does have them maybe change the scaling a bit

Cheers