This has happened to me actually, I think that it's the same for all games, not just F2P ones now. I have 20+ games not showing on the badges page where I've had all the drops and sold the cards, the only ones showing are ones I have badges for, drops remaining or that I've recently played. Shouldn't affect booster pack drops though, I got a booster pack for McPixel yesterday, it wasn't showing on the page at the time and it's not showing now after selling the cards.
Thanks for clearing it up.