This is a curious thing, thanks for the report. It seems like I have made a mistake somewhere or there is something weird going on.
Anyway, to fix this, go to Options and on the Cursor tab, change the setting to Never.
This turns off PNG compression for cursors (that would be the reason you are seeing garbage pixels in inkscape, which does not expect it). The weird thing is, if you set it to Always (to use PNG for all the images), the cursor looks fine (not blurry) in Windows 11. So, it looks like Windows is happy to accept the plain uncompressed cursors and also happy to accept the fully compressed ones, but for some reason does not like the ones, where only large images are compressed. Or I am generating these somehow incorrectly, I'll have to investigate this.