Comment # 14 on bug 1229237 from B

This is actually a GTK4 bug/regression. It's triggered when you have global
scaling AND a cursor theme with "nominal size" (the size you choose in the
Cursor Theme KCM) different from image sizes.

E.g. if you run xcursor-viewer /usr/share/icons/breeze_cursors/cursors/, you'll
see info like "Nominal size: 24. Image size: 32x32.".

But for xcursor-viewer /usr/share/icons/Adwaita/cursors/, it will be "Nominal
size: 24. Image size: 24x24.".

So it can be worked around by using a cursor theme like Adwaita.

there is already a submitted fix, but it hasn't been merged yet:

https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/7722