Bone Lagging Behind Parent

Hello, I am working on a rig and am having a problem where a child bone will lag behind it’s parent bone. For example, if I rotate the parent, then clear the rotation, the child will stay in the same position as before the clear rotation. It won’t move to the correct position until I update the rig, such as moving some bone or changing a setting. You can see the problem happening with the arms in the attached blend file. Thank you for any help!

Attachments

daniel.blend (1.47 MB)

It seems to happen when I add the “copy scale” constraint to the upper arm bone. I have no idea why though, is this possibly a bug?