Being a veteran of this forum, I do know of one case where this happened. Please search the forum. The situation was something like this. The guy's PD was NOT current from OCTOBER 2005 onwards. However, he received an approval in NOVEMBER 2005 or DECEMBER 2005. He was flummoxed as everybody did because his PD was not current at that time. When he received his welcome notice and GC, he was amused to see that it had an approval date of MAY/JUNE/JULY 2005 (pretty nebulous on which month precisely it was...but am very sanguine it was one of these three months).
Alas, this amusement turned out to be a bemusement for this dear friend of this forum when he saw that his wife, who had returned back to India on her H4 (she had some dissertation to complete before joining her husband back and to file for I-485) thinking that she can come back to file her I-485 as dependent as her husband's petition is stuck in the thraldom of retrogression, was rudely disappointed to see that she cannot come back to the US because her H4 is now untenable because her husband's GC was approved with a backdated approval date.
On MAY/JUNE/JULY 2005 (whenever his notice says was approved) his PD was current. But then the sixty-four-million-dollar-question is, if he would have gotten approved on MAY/JUNE/JULY 2005, why would it take several months later for this guy to know that he is approved. Remember, none of the systems showed that this guy got approved, because his beloved wife got her H4 stamping in Madras (India) consulate on NOVEMBER 2005 (just a few days before his GC approval letter came in mail) and even traveled to the US on H4B for a week or so only to return back to India to defend her dissertation.
I am responding to this thread based on my memory. I can vouchsafe for the facts, but am pretty nebulous on the exact dates. However, the ballpark dates I have stated are close to 100% right. I wish the friend who had posted this experience reads this to adduce more.
Hope this helps.
