As you level it it gains EVs which are not updated until you restart the client.
Please do not scan a pokemon if it's gained any combat exp (unless EVs are all already maxed when you login) without relogging.
You will need to delete this pokemons data and restart from scratch following this.
Edit: For those asking yes this IV and most others are 100% accurate.
The problem comes with the issue above where EVs do not update until you relog.
For those having problems missing the main class please follow the video as the only time I've reproduced that error is from trying to run the file from the archive instead of extracting it.