System Information
Operating system: macOS-10.15.7-x86_64-i386-64bit 64 Bits

Blender Version
Broken: version: 3.4.0 Alpha, branch: master, commit date: 2022-08-18 23:03, hash: rBf5aac6662d35

Short description of error
Tried with the old example given in the text for the series in the rip vertices, a plane subdivided by 3. With Alt-D the drag the mouse creating this strange appearance, with hole on the geometry:

Then if one change to Axis Orthographic to 'Z' (in this case), the hole is gone, leaving me in a rather confusing state of mind.

This image, however, is rather different from the example image given in the manual:

https://docs.blender.org/manual/en/dev/_images/modeling_meshes_editing_vertex_rip-vertices-fill_result.png

The original loop cut is no longer there, where as it exists in the example image.