Can't remove heightmap and colourmap after importing / colourmap turns gray

After choosing the heightmap and colourmap I can not remove them from the terrain editor.
Also, when I import a colourmap it turns into a grey tone?
I will attach a photo of the original colourmap:


looks like a studio bug, probs needs to be reported

I think the colors disappear because roblox only has so many materials so only so many colors can be used. kinda like a color palette limit

I was able to delete the height map by closing the place and opening it again.