Procedural foliage using inclusion layer is not being spawned correctly

When I add an inclusion layer to a static mesh foliage element that is being used by a procedural foliage spawner, the foliage does not spawn correctly when the spawner is re-simulated. Specifically, several of the tiles are not generated, and usually one tile is only partially generated. I set up the same content in a similar manner in 4.24 and it worked as expected. Problem is observed in 4.25 and in current 4.26 preview build.

Test setup is very basic: I created a new landscape and added a material with two blended layers named “Dirt” and “Grass”, created a static mesh foliage element with the default engine cube mesh, added “Grass” to the inclusion landscape layer array, added the foliage element to a procedural foliage spawner, added a proc foliage spawner volume to the level, set it to apply to landscapes and to use the new spawner I’d created.

Attached images show results: