Rotating landscape material on Android - UE 4.20.3

Hello everyone,

I’ve got an issue on our project, running on the Samsung Gear VR (Galaxy S8). We are using Unreal Engine 4.20.3 & we tested it on Unreal Engine 4.21 too. The problem is that on the phone, the landscape textures are rotating from the value we put in our custom rotator at regular time intervals. There is no issue on PC in play mode in UE4 Editor.
We built a landscape material with 3 samplers and 8 layers (screenshots).

You can find here how the issue looks like in the game on mobile :

We could put the rotation on the “LandscapeCoords” node directly (which is not bugged), but we would like a parameter on it to change it in the instances.

If someone could have an idea about why it is not working and how to solve this, I would really appreciate it !