The level-up detection in Flaming Durtles is solid by now, and the hourly automatic sync would have soon caught up anyway.
Based on a quick scroll back in this topic, I’m fairly sure HDshrimpkick still had an open session in the app. Finishing a session where a subject passes always triggers an extra sync exactly to catch this kind of situation, but if the session is kept open the app won’t catch up until the hourly sync.
@HDshrimpkick, welcome to level 5 
. If you’d like me to check out what happened in more detail, you can try to upload your debug log in the settings menu, or drop by in the support thread if you have any problems with the app in the future: [Android] Flaming Durtles - Android app with offline support