Bug? Skybox Shader Android

Hello there,

I'm developing a game with very high view distance (Far clip plane of Unity Camera is set to 10000). If I use a skybox shader generated with shaderforge (1.26 - latest) I get glitches on older devices (namely Samsung Note 2).

Via trial and error I found out that everything related to view direction (dot product of view direction, cubemaps) glitches out. Here is a screenshot of the default shaderforge skybox shader viewed with a camera with a far clip plane set to 8000 :

Using the default far clip plane distance of 1000 or using standart unity shaders, or some of keijiros magnificent skybos shaders (https://github.com/keijiro/UnitySkyboxShaders/) result in no glitchy behaviour.

What could be the cause of this? Even displaying just a cubemap directly hooked up into emission glitches out.

Best,

Jan