ios 15 and bluetooth always connected airpods

Hello; not if the topic has already been treated (I have searched but I have not found anything) in practice I have a problem with my iphone 12 pro max with the beta 6 version of ios 15 (19A5325f); the problem specifically concerns the bluetooth that I always remain connected with my second generation airpods (but the same happens with my airpods pro). In practice, making a phone call automatically, the call switches to the airpods even with the case closed and often going to the airplay menu I have to click on the small radar type icon to see that the iphone is always connected with the airpods even with the case closed I repeat. I also notice the automatic switch because the music menu appears in the lockscren. I ask you kindly, am I doing something wrong with the settings or is it an ios 15 bug? Tell me what details you need to better understand the problem. Thank you