Not sure 100% if this is your problem, but when you’re painting layers you’re basically “stack” them and not overriding. If you had cliff layer as base layer and then painted with grass it still has both layers. You can erase layer by holding shift while painting.
I meant painting on Landscape itself.
If at any point you painted Landscape section with Cliff layer and then repainted with Grass layer - you still have Cliff layer underneath so tessellation value from Cliff applied as well as from Grass. It might look like Grass, but actually it Cliff + Grass. To remove existing layer from landscape start painting on Landscape, choose Cliff layer and “paint” it with shift.