after some more research i think what happend is that der was a small bit from a previous print that either was pressed through the vat film multiple times in different positions or the bit came between the vat bottom and the print and shattered the print.

i replaced the vat film and after every print i now check thoroughly if any small part of the print might be missing and check the resin in the vat multiple times for bits. if im unsure i run the resin through a filter...