HA always has problems, as it's been running with 1980s pre-Internet era technology. It's 2023 and HA still doesn't have online check-in (not one that has ever worked, at least). That says it all..

The new GDS (same one that JL uses) transition has caused a lot of problems, yes. HA site says that still no flights can be booked there (since the 18th) and to book via third parties. But actually the opposite is true. On HA doing new bookings is fine (at least using HA miles). It is booking with third parties like AA that's a problem - the flights show, but can't be confirmed. As the flights I need have HA+JL connecting flights, I can only book it via AA; can't use HA miles for it.

I am guessing that AA hasn't fully updated it's connectivity yet to HA using the new GDS (AA still displays the old GDS PNRs that are no longer valid on HA, for example). But then again, AA does see the actual accurate inventory, just always errors out when trying to go and actually book it. So could be just as likely problem on HA end, that it's not responding back with HK (hold confirmed) when AA is trying to "end" the record and save the flights to the PNR to get it ready for ticketing.