Scenario editor game breaking bug with terrain tool wondering if anybody knows the fix, might be an old bug from pre DE

I’ve been trying to make a custom map, and have painted half the map with the terrain tool with no issues. I am now having the issue that my map is being completely ruined by this tool, it’s hard to describe so I’ll post some screenshots below to show what is happening. Basically I am placing terrain fine, I switch terrain and then it paints it with no texture, and then when I switch again it ruins the whole map (final screenshot).

I’ve tried with heaps of terrains, the issue happens with snow, african, texan etc. I really have no idea what could be causing this, game breaking bug. I have made a short Imgur album below.

Any help would be greatly appreciated :slight_smile: