I got the second limb out of the form and squared up with the sander.   peeled the tape to take a peek and glad I did...the back glass shifted down the form a tad, making the very end of it (maybe 1/32") stick out over the stop pin.  when the pressure was applied it cause the glass to bubble a bit right at the butt end, and cracked a little too.  doesn't go more than 3/8" up into the limb so I think I can avoid it in final limb shaping (and it will be covered by a limb butt overlay anyway.)