When a domain name expires, it isn’t awarded by auction to whoever is fastest. For example, at NameSilo, the original owner still has a 30-day grace period to renew the domain, even if there are active bids on it.
I spotted the same issue with the Lovable team (including the CEO). They still had the old handle on their profiles, even though they moved to a new handle. No redirect.
It seems that Twitter hasn’t fixed it, and it’s been about a month or so.