Synopsis
One of the test stations in the VR scene from XR-Interaction-Toolkit-Examples-Internal includes a text field.  On Quest One when I selected the text field, a virtual keyboard appeared.  I typed on the keyboard and the characters appeared in the field.  However, when I do the same thing on my Windows MR HMD, no characters appear in the text field.  

Configuration
Unity 2020.3.44f1
XRI 2.3-pre.1
Scene = XR-Interaction-Toolkit-Examples-Internal/VR/Assets/Scenes/WorldInteractionDemo
Build Settings = UWP
XR Plugin Provider = WMR
Acer Windows MR HMD
Universal RP

How to See the Bug

If you have trouble seeing this bug using your own local repo, my project is attached in case this turns out to be specific to my settings.

If your project path is to long then you will get build errors.  I ran my test from c:/VR.

Using Unity 2020.3.44f1 open the WorldInteractionDemo scene.

Verify Build Settings and Project Settings per Configuration above.

Build and Run on your Windows MR HMD.

Navigate to the text field and select it.

When the virtual keyboard appears, type on it using the hand controllers.

No text appears in the text field; this is the bug.