Pokémon Go Plus useless

Since about two updates ago my app refreshes after I have another app open or put my phone to sleep which causes the pogo plus to constantly disconnect. Which means it is not tracking steps or anything. I have deleted and reinstalled the app, but it still closes. My plus is essentially useless since I need to keep the app open all the time.

TraciM about Pokémon GO, v1.29.1