This bug started happening to me probably after the latest 9.2 update.
1) Prepare a flat preset, with all parameters 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 Gradient and Radial filters 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 Gradient/Radial Filters. 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 Radial Filters: they have not been removed. Parameters in various panels have returned to their neutral position as expected, but every the Radial Filters are still there. This was not happening in previous versions of Lightroom. This also happen with Gradient Filters as well.