Yeah the transparency regarding the issue despite having everything linked up properly is saddening. They should at least make a post acknowledging the problem that's happening to those with everything set up correctly. Made a post myself detailing my problem and they automated bot the thread while linking the same "fix" that we've been using, implying they didn't even read it. Even sent a DM to one of the skate devs and not a single response back.
To my knowledge, from what I've read here, is that they're limiting access to the playtest which is why some people can't access it despite being properly linked up. Either send out too many codes and they messed up on their end and had to limit it or NDA breaks that some did ruined our chances of attempting the playtest aswell. If you were able to login beforehand you're set for the rest of the playtest but if you never got in then you're SOL until early access. If there was more of an explanation as to why this error is still happening to us then we could try to work around it but as it currently stands we are technically NOT invited to the playtest despite getting an invite.
If my assumption is wrong I'd happily eat my words but with how little communication there is about this issue with us I want to say it's safe to assume that's the case.