I have this problem every time I do a scan blitz. After scanning, not all the planets I discovered show up consistently in my planets list. After a while, the issue goes away, but until then, my planet list has a 10 planet range (currently anywhere from 80 to 90) that shifts. I have currently found 96 planets. I have cleared cache, reloaded game, reloaded the planets tab, etc.

This is probably a session issue. Note that because the game's session is tied to your Facebook session, the only way to clear your planet cache is to log out of Facebook and log back in.

Got it. Thanks!