This issue can be reproduced when connecting to a GNOME desktop from the Windows client. Set Windows display settings to have "Scale and layout" at 125% or above. When the client displays the remote GNOME desktop, the cursor size is smaller than what should be.

This is usually unnoticed. Increasing the scaling factor in Windows display settings makes it more evident.

The cursor size can be compared by activating "Show remote cursor pointer" in NoMachine Input settings, as the remote cursor size is not affected by "Scale and layout": local and remote cursor will show the same shape with different size.