Well, this last time that i used affinity to do real estate hdr merges, this issue did occur after every two sucessful hdr merges. I could do a recording, but all you will see is how the error message pops up on the screen. When i got the error message, i then tried to save to the desktop and got the same error message from the mac system. Here is the text of that error...
"Failed to save document: /Volumes/MotherShip/MS Home/*The Photo-Biz-IMAGES/Jobs/2020/Evolve/10716 Ponderosa/Finals/MasterBth2.afphoto. Save failed because you do not have permission to create a file in that location. Do you wish to save the document to a new file?"
FYI, that error message would say the same if i tried to save to the desktop folder, with the desktop folder listed in the error message.