Hi Paul,
Thanks for the update and the photo. Based on what I can see, it’s possible that the issue could be a blowout as a result of cupping. This happens when air or resin gets trapped during the print, and different printers can experience different peel forces depending on the resin and tank conditions. Re-orienting the part or adding drain holes could help fix that if it’s the cause. Drain holes can now be added directly in PreForm.
If you’d like, I’d be happy to take a look at the .form file if you can upload that here.