Pasteing AI over existing envelope points also seems a little buggy, notice if you move the AI after a paste that there are some missing points on the underlying envelope. (NOTE: Auto add edge points was disabled but doesn't change outcome).
v5.941,
Now in Pre11, when you move the AI notice the existing points have been deleted.
v5.95Pre11,
I'm not sure what the new behavior is supposed to be, Just thought I'd mention its changed.