Something similar happened to me.
Try doing what I did (admin have since said it is OK).
Re-register as maybe "Clawinus2" (I was "keyhoti" until I got the same sort of prob you are having, but when I tried re-registering with that nick I got the message that it was already in use - except it no longer appeared when I logged in - but as I didn't want to confuse myself or anyone else with an entirely new nick, I switched to "keyhoti2").
After doing this I checked my profile under "keyhoti" - by opening an earlier posting - and it was/is still there. Then I repeated what I had entered in my new "keyhoti2" membership.
Maybe admin has a better solution, but this worked for me and Bob (administrator) said that tho' it is better not to have two memberships (in effect) it's OK.
I have just joined as a member. While I am in one of the forums it shows me as a guest. Then, when I login I get neither a confirmation nor a rejection and am still shown as a guest. However, when I switch over to the feedback forum, all of a sudden, without entering my login information again, it indicates that I am logged in and shows my username. If I switch back to a technical forum, I once again lose the login status.

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