My computer can't run the latest Indesign so I'm happy with the new Convert option so I do not need idml files. But I think there is a bug sometimes wich shifts the startpage number to "2" instead of the original number "1". So now I check all converted files directly on startpage number.
Happend several times now, but not always. I noticed since book do not have even number on right pages 🙂
I do remember many bugs from idml to indd. And with page numbers too. Don't worry - check by your eyes all publication, this is our work for. Better to have working indd from idml than slowpoke and bugged by some reasons indd.
Wild and crazy thing for me — when object layer options from .psd is resets after converting to idml. Few times it cost to me days of resetting layers again.