This bug started happening to me probably after the latest 9.2 update.
1) Prepare a flat preset, with all edits set to their neutral position, and no local adjustments.
Let's call this preset "Rawest". Make sure everything is selected when you save it, especially the "Graduated Filters" and "Radial Filters" options. Now, this preset is supposed to restore everything to flat and remove any local adjustment, when selected.
2) Pick a photo, and select the Rawest preset. As you can see, no local adjustments are present and everything is flat.
3) Edit the photo and add some local adjustments. Here I added 2 radial filters, one on the top-left corner, and one on the face of the horse.
4) Now select the "Rawest" preset that you created in the beginning.
5) Look at the local adjustments: they have not been removed. Parameters in various panels have returned to their neutral position as expected, but every local adjustment is still there. This was not happening in previous versions of Lightroom.
A Snapshot after you first import won't work as it is the the same as if you used the Reset button. Unfortunately the Reset button and and initial Snapshot include the edits you used in an import preset or Camera Default. The only thing that worked was Reset(Adobe) which was removed as a feature in 9.?.