So, I exported using ‘simple unbroken sequence’ ie lose clone info. Up to frame 20, all was fine, after that, every clone has .hold on the end of the filename
(can’t work out how to insert an image to show you)
Yes, this is a bug and reported elsewhere on this forum. This happens if you export “simple unbroken sequence” together with “Combine Layers” checked. This is fixed with the next update which will be in a week or so.