Hello Mrbru06.
Thank you for using Apple Support Communities. It sounds like you're experiencing issues with your AirPods disconnecting. Specifically, they disconnect with your Apple Watch timer goes off. We can understand how this would be an issue. Allow us to investigate this issue and assist in any way we can.
We'd like to recommend some basic troubleshooting steps to see if we can help get this unique issue resolved. We can start by restarting all your devices, iPhone and Apple Watch. You can also attempt to reset your AirPods as well:
Restart your iPhone - Apple Support
How to restart your Apple Watch - Apple Support
How to reset your AirPods and AirPods Pro - Apple Support
Additionally, if you have any pending updates available for your Apple Watch and iPhone, it would be a great step to update them. Keeping your devices fully updated can help resolve various issues and also help with overall performance. Just in case you're not fully updated, the resources below can guide you:
Update your Apple Watch - Apple Support
Back up iPhone - Apple Support
Update your iPhone, iPad, or iPod touch - Apple Support
Feel free to keep us updated on your results. Cheers.