Post-interview F4 retrogression question

[DAndy127 0]

My parents adjusted via my USC aunt. They filed the I-130 in April 2001 under 245-i. They were finally eligible to submit I-485, etc. in August 2010, and finally did so with a lawyer in November 2010. Things moved along quickly and their interview was scheduled for and held in February 2011. That same month, the priority date retrogressed two years back to January 1, 2000. They tell me the interview went well and that they think everything was approved, but when I log in with their case number on the USCIS site, it still merely says that their interview letter has been mailed and that their interview has been scheduled.

Is it possible that all updates / progress on the case was halted that same month? Is this typical for people who were affected by the F4 retrogression? Is there any cause for concern here since we don't see any decision activity? I realize that this doesn't change the fact that they must still wait for their priority date to become current. Thank you in advance to anyone who can enlighten me on their situation!

[SimonZoe 4]

I also have the same question.I was informed all the necessary documents have been received and they will arrange my interview very soon---till now.