The snap cursor internally snaps to the Face to define the occlusion of
the Grid or to calculate the "Surface" orientation set by the tool.
Even though this is not the snap point enabled by the user, this
internal Snap to Face takes precedence over the Snap to Grid that is
enabled by the user.
To solve this, the solution is to do a second snap test but now only to
Grid and using the hit point as a reference for the closest grid.
Also fixes Absolute Increment Snap not being detected as Grid by the
tool.
Pull Request: https://projects.blender.org/blender/blender/pulls/130092
b4154c6a0e