I feel bad to constantly be bringing up issues like this, new one i've encountered seems pretty serious though. When I set the parent of a bone (or a bone hierarchy) that contains bones constrained by an IK or a path to a bone that has a path constraint (maybe other constraints break it too), alot of weird stuff happens.

As you can see in the picture, Two eyebrows that had bones constrained to the paths, the mesh was bound to those bones. When changing the parent bone they warped unusually. I have been able to get around this by unbinding the mesh first, doing the parent change and then rebinding them.

The other thing, a little less obvious at a glance, is if you look at the hair bone to the left that was bound to the IK, initially the bones are obeying the IK, after the reparent they no longer respond to the IK.

Steps to reproduce

1) Create a bone or path attached to either an IK or path constraint
2) Create a second bone, attach it to another path constraint
3) Drag the first bone into the second bone
4) Watch everything get weird

Something else to add to this, the paths are also breaking in this process, hadnt noticed it earlier but the bone placement along the path changes and no longer responds to change through the constraint.

Oh right I didn't even realise that the constraints were ordered XD You're a life saver