Thanks for notifying me. I am investigating, though also am trying not to get too side-tracked back into web dev again ;p.
There are a couple issues I see and am trying a few quick setting changes.
I don't know if it's related, but the account bridge between the main site and the forum is either malfunctioning, or at the very least I need to define the expected behavior so we know what happens when there are pre-existing accounts at the forum that contradict the main site, and other scenarios.
However, this login issue I think is some server setting. Please hold, let me play around

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Curiously, it doesn't happen to me. However, on another system I am unable to log in at all, due to the lack of real IP discovery I think, causing it to hit the max attempts per IP. All traffic is first routed through a reverse proxy firewall these days (couldn't otherwise stand the risk of a 0-day exploit).