We noticed something playing a private lobby last night.
When we are at the screen where host can select the game-mode and options, the player Level that they gained while playing, is incorrect.
But if you go into your profile, go to your badge and just click the Save button, then it updates the level indicator in the lobby.
Sometimes does that with the badges too. You join in and it shows the default badge instead of your custom badge until you go back into your profile and click save.
We all panicked the first time we saw it thinking we lost 4-5 levels we had just gained.