You are on there now ...
https://en.numista.com/catalogue/pieces2691.html
I don't think it is to do with rated swaps, more like site activity in general.
Maybe after six months a member gets put on a list of inactive accounts, so as you
Joined: 19-Jul-2011 then perhaps on 20-Jan-2012 that may be what happened to your account. But then you writing on the Forum made your account active again, on swap pages - as shown above.
P.S. Or your swap 22-Aug-2011 would make 23-Feb-2012 (my birthday as it happens) the date the above system would begin - but I am guessing. Anyway, you are showing on here again, as mentioned!