I've made some parts that were under vacuum and cured for 24h.  They were then post cured in the moulds for 8 hours at 60 deg C.  I've pulled them, trimmed them and lacquered them and I've found a slight movement in the moulding.  Its a scoop and its 'opened out on its edges.  Any ideas whats caused it and how I can stop it?  I can flex the moulding back to how it should be to bond the grilles in (about 4-5mm out)  but I'd like to be able to stop it in the future.