references to interfaces remain in blueprints after being deleted when copying functions

If an interface is deleted from a blueprint and the functions are copied over references to the interface remain in the reference viewer of the editor.

1. Create Interface with a function (1 input param, 1 output param).
2. Create Actor BP, implement interface. Compile/save/etc.
3. Check Reference Viewer for the interface. It should show the actor BP as something that references it.
4. In actor, remove the interface. When asked to copy the functions over, say yes.
5. Check Reference Viewer for the interface.

Expected: It no longer shows the actor BP
Actual: It still shows the actor BP