Physics Objects fall through each other, but only when one is touching a non-physics object

Background: I’m making a game where the player can pickup objects.

To do this:

  1. Disable physics on the root mesh if enabled
  2. Attach to component

Then, to drop:

  • If the actor is supposed to simulate
    physics, simply enable physics (which
    will detach it automatically)
  • If not, just detach from component

Now, the actual issue arises with detaching physics object. If I try to place a physics object on top of another physics object, it behaves strangely:

I’ll call the object I’m trying to put down the “top” and the object the top is going to sit on the “bottom”.

If the bottom is sitting on top of another physics object, it stacks perfectly. BUT, if the bottom is sitting on an object that is NOT simulating physics, the top will fall into it, clip through, and then pop out, sending both objects flying.

Can anyone help me figure out why this is?