We got our 2nd FP notice after 30 months since 1st were done (so technically
this should have been the third)
So not to worry too much.
It's not your responsibility to track the FPs.
If they need them, they'll send the notices.
It's not that GC will not be approved without those. Once your cases
are near approval, they will check and send the notice.
Only thing you might want to make sure is that you have not missed the notice.
If you have moved and notified USCIS, then you'll get it when they want them.
Take it easy.