There have been similar threads previously. Basically sometimes VFR flights show up and sometimes they don't, it's an FAA computer thing.
I would like to respectfully disagree. I believe these are two separate issues.
Yes, not all VFR flights show up on FA and that is due to the fact that not all flights are entered into the NAS. But if they are, they should show up. And that is a brand new bug. I posted a separate thread
I noticed the same thing: a few weeks ago, FA stopped showing some flights. I remember actually having seen the flights after I've performed them but now they do not show on the map. (though the flights are in the FA DB and show up on the history page)
Also, I cannot see IFR flights either. Scheduled airline flights etc. No flights show up on the map for me. So this is definitely a bug.
FA folks, please look into it and bring our flights back.