Why does ManualSurfaceJointInstance crash your game/server?

I know some people use it in Admin scripts, but why does it crash your server/game when its added?

I don't think there's ever been a explanation for why it does this.

My guess is that is a abstract class which normally can't be made, but for some reason this one can and that causes ROBLOX to crash when its made.

If you have any questions, concerns or just need some help with this PM me on ROBLOX!