Sorry I don't have recording software on my potato, but I have noticed occasionally and across different Mons that sometimes you will "gain" multiple levels from feinting an opposing Pokemon that doesn't accurately reflect your actual level. It goes away after battle and as such doesn't seem exploitable since moves are learned after battle but it "might" affect moves like seismic toss and night shade that are based off your level depending on how the system calculates this so I'd rather waste a report than not say anything. Thanks everyone and hopefully this helps.

Hello @Tengrikun. My apologies for the late response.

 

This bug is purely visual and has no impact on the actual level of the Pokémon. The level displayed after the battle is the correct one.

The Developers are aware of this bug, but it’s hard to say when it will be addressed since there are more pressing matters to attend to.

 

If you have further questions, please let me know.