Pokémon go plus constantly crashing

My bf and i love this game, but while his Pokémon go plus is linked to his (android) phone for an hour, during the same hour my (iphone) go plus is constantly crashing. The app is crashing a ridiculous amount which is disconnecting my go plus. Ive tracked it crashing about 10 times within an hour and its driving me nuts! Every time i go to another app with it running in the background it crashes as well. Sometimes just being on the screen for a while it will. If the bugs for iphone could be fixed for this that would be great.

Rose tattoo? about Pokémon GO, v1.39.1