https://commons.wikimedia.org/wiki/Special:CentralAuth/Alexis_Jazz shows I registered in 2008, but I have a welcome message from 2007. @Fae said on https://commons.wikimedia.org/w/index.php?title=Commons:Village_pump&diff=300160331&oldid=300159265 "That's a GAM bug as commonswiki_p has your registration date at 2007-10-13 05:23:20."
I'm not sure if this is the same as T170372 and T169416. Those are closed but the issue doesn't seem to have been resolved. (or this is something different)