Per,
I have an Anycubic printer that uses Photon workshop to slice the files. Photon workshop won't run very well on my computer, but Prusa slicer does. So I use Prusa slicer to prepare the prints, hollowing, holes, supports etc, then I export the file as an STL into Photon workshop to slice. Thinking about the problems logically, and having watched a youtube video this evening where the poster had a FEP film with as many bumps as mine, I think it was me preparing the print in Prusa that created the problem. Not enough supports and not beefy enough. I will try again.
Lee