Landscape material switch

I’m creating weather and seasons system.
For all seasons I have a landscape with a common topology. Materials and layers re different.
So when the level is loaded I need to change the landscape material.

I’ve created a test project where I have two landscape master materials. Both of them have with two layers. The second layer is shared between both materials. I also have three material instances: MI_First and MI_Second contain grass and sand layers, and MI_Third contains snow and sand layers.

Here is what I get when I apply those materials to the landscape manually:




Black areas on the first and the second screenshot, and the blue one one the third screenshot match. My guess is the layers weights are a part of the landscape. And the weights don’t change when I swap the metrial. Is there any trick to fix it? Or is there any other method I’m not familiar with?

Here is a screenshot that shows how I change the material dynamically in the level blueprint.

And it’s not change visual if i set material from level blueprint like this.
Parent of the instance is correct but the visual does’t change: