I'm migrating from a 32b OPNsense system to a 64b system and importing seems to work with some hiccups.
Is this even possible if the versions match but the bitset doesn't?
the config is stored in xml format, and as there is no difference in the options between the 32/64 bit versions there should no problem importing the settings.
Just remember than some settings won't become active until re-install any plugins you may have installed and will require a reboot after applying the settings
What kind of hiccups then? There shouldn't be a difference except for network configuration issues because your NIC names likely change, but that is not a 32/64 bit issue.
Cheers,
Franco