JAL's website and app are absolutely abysmal, indeed. Their system is so bad that it even nearly got me IDB'd for one of my flights, had I not insisted on the airline fixing the issue over the phone. The issue was related to signing up for a JALCARD, and how the bank's decision to register a combination of my middle name and last name as simply my last name eventually carried over to JAL's reservation systems, causing an ID mismatch.

On a typical day, it feels like a crapshoot whether I'm even able to properly log into my JMB account without some weird error occurring.

Not sure what JAL's issue is but they need to improve their IT. ANA isn't much better but I've had fewer issues with them.