In previous versions it worked fine (2.9.6), but I had already seen this bug in older versions, I'm not sure which one, possibly 2.9.2.
I have a an Ugee M1000L pressure tablet, and two 1920x1080 monitors, the tablet is setup to work only in monitor 1, and works this way in every software. As soon as I turn to the brush tool in Krita, I see a double cursor while inside the canvas: one in the correct position and one that acts as if the work area of the tablet was the 2 monitors, and this second cursor is the one that does the brushing. That is to say, the left side corresponds to the left side, but the right side of the screen corresponds to only the middle of the tablet.
If I temove the second monitor it works ok.

Reproducible: Always

Steps to Reproduce:
1. Have a dual monitor system
2. Setup a Ugee M1000L to work only in monitor 1
3. Use brush tool in Krita

Actual Results:  
Brush acts as if the tablet was setup to work on both monitors, so only the left half of the tablet is used, and the traces are stretched horizontally

Expected Results:  
Whole tablet surface should correspond with monitor 1, as happens with every other software.