Colliders run slower on animated objects?

I have a character animated with bones.

Each bone has a capsule collider on it, to capture collisions from the player's weapon.

The capsule colliders themselves do not collide with each other (as defined in the layer collision matrix).

Also, each capsule collider has "trigger" turned on.

When the bones of the character are animated, the physics simulation of the scene (as listed in the profiler) takes approx. 100x longer than when the bones are not animated and the colliders are motionless.

Is there a reason for this? Why do the colliders take longer to "simulate" when they're moving, even though they're not colliding with anything?