Exactly the same issue here - definitely a bug in IOS 13 (I’m on the latest patch and the issue continues).
Steps to resolve have to be carried out each time I want to use the Powerbeats Pro.
- Access Bluetooth in settings.
- Select (i) icon next to device name and select ‘Disconnect device’ if not already disconnected.
- Select ‘forget device’.
- Put both earphones in the Powerbeats Pro charger case and hold down the ‘Reset’ button for approximately 15 seconds (until the light on the front flashes red and white simultaneously.
- You should now see the ‘Connect’ pop up display on your iPhone (as if connecting the earphones from new).
- Follow the connection steps - and all should be ok (until the next time you want to use them).
I selected ‘No’ to Siri and Announcing Messages.
I suspect the code for earphones has been altered to account for AirPod Pro - and something has gone amiss for Powerbeats Pro in the process.