Based solely on my observations, I believe the answer is "Yes".
Anyone who registered in the last year will have to start over again.
It appears to be even worse; I registered between 1.5 - 2 years ago and all my info is gone as well! Being in IT for 3 decades - I wish that was an exaggeration, but I am indeed that old - means I know that anything considered important is always
backed up. If it's really important you have two copies. User information seems like it should fall into the second category. At the very least, the first one.
I'm not in the position to make 500 posts a year - so losing all my stuff isn't quite as critical as doing the same thing to a person who is very active - but it's still frustrating to no longer have my post count, subscribed threads, gallery, etc. This shouldn't happen to critical data.