Prevent a Capsule from Tumbling Down

I’m making an Actor Component that does input movement calculations for Pawns, but I want to use the physics simulation for gravity, impulses and hits. It works for Sphere and Box Primitive Components, but not for Capsules, they tumble down. How to not tumble down?

EDIT: Whenever it collides with a physical object or after rotations, It actually starts to freak out as if it had an input of its own. The Movement Actor Component is Pre or Post Physics, while the collision component is During Physics.