Bluetooth RN41 / RN42 and Windows 10

I've been using the RN41 bluetooth module with a custom board flashed with the Arduino lillypad USB bootloader and encountered some problems with unreliable bluetooth communications. At first I put it down to problems with my hardware but it now looks like the latest windows 10 update KB3194798 might be the culprit.

I've tested my hardware using a tablet to connect to the bluetooth and it works fine.

The problem I've been having is twofold: 1: When I try and pair with an RN41/42 device it asks me if the passcode matches the one on the screen (and displays a 6 digit number). These devices do not generate a passcode, they expect a 4 digit PIN to pair them and previously windows 10 has asked me for this PIN whenever I pair with an RN41/42. - This looks like windows is using an incorrect protocol for this class of device ...?

2: If I just click 'Yes' it will usually pair with the device, but when I open a connection using any serial terminal (The Arduino IDE one or others like Realterm or Termite) it will display data for a short while before freezing. When I stream data at 10Hz it displays in the terminal in a rather jerky fashion, almost as if the BT driver is randomly buffering lines of data ...

Has anyone else experience this type of issue in the last few days ... ?