https://wccftech.com/experiencing-windows-10-bluetooth-speaker-issues-heres-how-to-fix/

Microsoft has published a support document explaining a Bluetooth issue introduced by the Windows 10 July 2019 Cumulative Update. The company explained that after installing this update (KB4505903) on Windows 10 May 2019 Update (version 1903) on a computer that has an internal speaker installed, you might experience one of the following issues:

“Additionally, in Device Manager, you notice an entry under the Sound, video and game controllers node for Microsoft Bluetooth A2dp Source that shows a yellow bang (exclamation mark) icon,” the Windows maker added.