Airpods Pro Gen 2 disconnecting from Apple Watch 7 Cellular when on a call

I took a walk today and I left my iPhone at home, I only had my Apple Watch 7 Cellular and the Airpods Pro 2nd Gen.

I have initiated a call on my Watch during my walk, and everything was fine during the call until I have approached my house (where I left my iPhone) on my way back to home where my Apple Watch suddenly switched to their speakers, but I was still on this call. I was basically in front of my house, at a 5 meter distance between me and the iPhone.

I have discovered that the same situation happens when I leave my iPhone in the house and I go to the balcony with the Watch and the Airpods and I initiate a call. It randomly switches to the speakers of the Watch. It is so annoying.

My guess is that if the Airpods leave the Bluetooth range of the iPhone then they disconnect from the iPhone, once they get back into range they connect again to the iPhone too, which is perfectly normal. I just can’t explain why the Apple Watch switches to their Speakers? When the Airpods are connecting to the iPhone then they disconnect from the Apple Watch? If I‘m listening to music everything is fine, it happens only during calls, and only in this specific situation when both the Watch and Airpods are disconnected from the iPhone because of the distance, and they get connected back to the iPhone when they get back into range.

Apple Support told me to send them to the closest Authorised Apple Service Center. I tried factory resetting the Airpods more then 10 times using the steps on the Apple Website. I also removed them from Find My, and connected back. I tried setting “When last connected to this iPhone”. Factory resetting the Watch and iPhone and Airpods at the same time. None of this has solved my problem.