Material Undo Bug

Can anyone help me with my issue?

I start a blank project with starter content and create a bunch of BSP brushes (boxes). I apply materials to some faces. Hitting undo (ctrl z) doesn’t undo the materials I applied to the surfaces. I checked the undo history and every time I apply a material to a surface, it creates a “Create Actors” in the list and undoing that does nothing. I tried dragging materials onto surfaces. I tried selecting surfaces and shift clicking them. I tried alt clicking surfaces. All these methods fail to apply an undo-able material. Tried on version 4.12.13 and 4.11.2 and have the same problem on both. Am I doing something wrong or what?