I tried to reinstall Pokémon Go today, and the issue not solved yet. Seems is a bug, the Pokémon Go Application automatically running on the background, even you closed the application.
You may check if your problem is same with me:
- Close the Pokémon Go application [Background too].
- Wait until the your phone have some random vibration again.
- Click on your Pokémon Go Apps. The apps will show as main page, instead of loading screen. [Due some glitch and cause Pokémon Go running on background randomly].
- The Pokémon Go character is going full black, and having a glitch text.
Here's the developer PSA:
"To resolve this, Niantic suggest that you should refresh game data under the advanced settings option in game.
As for the random phone vibrations you can turn off notifications as there isn’t a clear solution at this time."