What you are seeing is high cost and low precision within the pixel shader on the mobile device. The solution is to use customUVs to calculate the panning. So click your base material node and find the field where it specifies number of customized UVs. Make it at least 2. Put your panner nodes into the UV2 input node.
Then place a regular texture coordinate node set to index 1. If there is something hooked up to CUV1, it will overwrite the UV1 node with the vertex shader calculation. The UV1 node should have tiling options at default. Vertex shader way faster (less verts than pixels usually) and has better precision too. Then just use that regular UV1 node for your panning texture.
Try doing a search for custom UVs the doc page on them is pretty thorough. I’d find it but I’m on ipad on vacation going from memory 