Pokemon-go – Pokemon Go Trainer club account got reset after update

Characters and progress are tied to accounts, so if your son wants to hold onto his, he should log in with the Pokemon Trainer Club as before.

If the app isn't doing this even after a restart, the best option is probably to uninstall the app and download it again from the Google Play store. This won't harm his progress.

The CP of the Vaporeon you just powered up has increased correctly, the thing here is that you have more than 1 Vaporeon and there is a glitch that when you power up a pokemon and it's CP increases more than your next higher CP, it switches place, so it seems you lost some CP on that one.

Like this:

1. Dragonite CP 1020
2. Vaporeon CP 1010
3. Vaporeon CP 1000

If you power up the #3 CP 1000 to CP 1015, it will switch on the list to #2 but previously you were seeing the #3 on the list, so now it will display the CP 1010 and will seem to lose some CP, but you are looking at a different pokémon.

1. Dragonite CP 1020
2. Vaporeon CP 1015 ← powered up
3. Vaporeon CP 1010 ← seeing this

The same will happen after you power up the CP 1015 again:

1. Vaporeon CP 1030 ← powered up
2. Dragonite CP 1020 ← seeing this
3. Vaporeon CP 1010

You powered the Vaporeon CP 1015 to CP 1030 but that one was the #2 on this list and became #1, but now you see your Dragonite as it becomes the #2 on the list.

I hope Niantic fixes this soon.