So we seem to have developed a problem with Filled Regions and they only display solid fill and hatches in black unless we go into "Override Graphics in Viewport" and change the surface color there. This is really an issue when trying to set "Solid Fill" to a grey tone. At first I thought it was in a view template because the colors were working fine in one but only showing black in another. So I started to go through the viewport settings for the suspect view template until all the setting were turned off. So it's not a viewport template forcing it to always be black, but clearly there is a viewport template that is allowing the Filled Region Color to show according to it's setting int he Type properties>Graphics>Color setting.