Thank you for your message.
Windows 10 fully supports the hands free profile (HFP), and all Bluetooth headsets have to support either that profile or the headset profile (HSP), which is also fully supported in Windows. However, the Bluetooth headset has to be set as the default communications device. There is a difference between these two profiles which allow for two-way communication but with mono, telephone-quality sound, and the audio A2DP profile which allows only listening, but with stereo, CD-quality sound.
There have been problems with 1803 on some computers, but it is more likely something in the details of implementation, rather than the elimination of something as important as support for an entire class of Bluetooth devices.
A more likely cause of your issue is a driver or device conflict in your computer. It often happens that a major Windows 10 upgrade replaces a driver or enables a previously disabled device, that then causes conflicts with other drivers or devices. The Windows Bluetooth software is not the most robust, and it is pretty sensitive to things like this.
I see this a lot and it is something we can usually resolve. If this is the issue, it will show up in the diagnostic files.
Along with sending the diagnostic file, could you please tell me the make and model of the headset you are trying to connect through the Plugable adapter?