1. Rez a prim
  2. Set material to PBR Metallic
  3. Click Texture Picker and set material to Blank
  4. Edit Selected material and Base Color, ORM or anything else
  5. Attempt to remove material using Texture Picker and Selecting None
  6. Any edits are removed, but the Blank material remains on the object
  7. If you select a saved material from Texture Picker, the material can be removed by using Texture Picker and Selecting None. This is the expected behavior.