Sound issues with streaming with app

Hello, We are and have been 2year XFinity cable, Internet and streaming customers. We are using the Roku access on the streaming TV’s. All others apps work beautifully but the XFinity app has consistent issues. We are looked for updates, uninstalled and reinstalled and we are currently experiencing sound issues. The sound volume goes down. We exit and no other apps have the issue as the sound then goes to normal. We go back into the XFinity app and it works for awhile then issues again. Please help!