Landscape Grass disappears after sculpting a landscape with "Enable Edit Layers" on

The grass won't spawn after proper material being applied on the landscape. Even after being forced to be spawned (by reloading the level, for example) the grass will disappear again every time the sculpt tool is used. Everything works as expected if Edit Layers is disabled.

This was reported and tested in 4.24.3 (CL-11590370). This was reproduced in 4.25 Preview 4 (CL-12366721) and Main 4.26 (CL-12620833).

1. Open the UE4 Editor and create a Blank project
2. Create a Landscape Actor with "Enable Edit Layers" parameter enabled
3. Create a Landscape Grass Type with one or more array elements.You can use a default cube static mesh as an element.
4. Create a Material with a Landscape Grass Output node. Add the Landscape Grass Type created on step 2 to that node. Attach a Constant3Vector on the Grass node.
5. Apply the material created on step 4 on the landscape created on step 2
6. Sculpt the Landscape

Results: The grass won't spawn over the landscape after the material is applied and/or disappears when the landscape is sculpted

Expected: The grass should spawn over the landscape right after the material is applied or the sculpt tool is used.