I was playing with the grid width of a column, and I clicked on the “infinity” symbol at the very left of width settings in “appearance”. This changed to width to some crazy value like 7.558. I then clicked the infinity symbol a second time and the value “7.558” disappeared AND the column background color disappeared. Also: the arrows for increasing or decreasing the column grid width quit working altogether.
See video: https://www.loom.com/share/d9618c5bfa9643b18cd9829fe4120b71