OSK doesn't show after disconnecting bluetooth keyboard

[Tomas Öqvist]

Device: Bq Aquaris M10
OS: OTA-10.1

Steps:
1. Connect BLE device (MS foldable Kb in my case) according to https://bugs.launchpad.net/ubuntu/+source/ubuntu-system-settings/+bug/1576986
2. Turn keyboard off (in this case, fold it) - bluetooth indicator shows no devices connected
3. Tap on a text field

Expected result:
OSK appears on screen

Actual result:
OSK does not appear

Repeat steps 1 & 2 above
3. Turn bluetooth off through indicator or system settings
4. Tap on a text field

Expected result:
OSK appears on screen

Actual result:
OSK does not appear

OSK only returns after rebooting the device.

I might add that the MS foldable keyboard (as described in bug 1576986 above) is not visible in the system settings even though it is connected and working with the tablet. However, the bluetooth indicator is highlighted until keyboard is turned off (folded).