Texture artifacts on device?

Hi, I have a 3d model with a texture. It looks great in the editor -- the color is nice and flat, the way it's supposed to be. But on device I get some strange rendering artifacts. I don't see these on other objects in the project, but I don't know what could be causing them. I use deferred rendering on all my cameras.

Here's a picture of the problem from my device (I need point filter mode and no compression in order to make the voxel art's texture look nice look not blurry, and I turn off the mip maps to save memory), and the import settings for the texture:

And here's a picture of my graphics settings. Note there is only one quality level, ultra.

Finally, here's a picture of the shader that is being used:

https://imgur.com/a/NjpXX2C

Many thanks!