Reproduced on:
Version 2019.3.0a10 (7c94a84d850a)
Sat, 13 Jul 2019 06:10:10 GMT
Branch: trunk

Summary:
The terrain doesn't render using the base map after to it, for Paint Texture.

Repro:
1) Open up the attached project.
2) Open up the scene NewScene1.unity. The scene view camera should open up far away, but if not you can use the view the Main Camera (Game View) has.
3) Draw the Ice Texture somewhere on the terrain.
> Once you stop painting, you should notice that the terrain doesn't return to using the basemap.

Note:
- If you paint with the Raise or Lower Height brush, it will return to using the basemap after you're done.
- You will need to reload the scene in order to reproduce, or draw height then switch back to draw texture.