Has anything happened in this site ?

Hi, admin/moderator
Although I'm not very active in this forum, only read/haven't posted a lot 🙂
I registered here in Feb this year and then I have had a few post. Recently I tried to logon again and found that my id is no longer valid, then I registered again using the same id, my original welcome message in Feb still in my PM inbox. Is this something unusual or an Id will be deleted if it has been inactive for some time ?