Unity Lighting, marks on textures

I’m having an issue with baking the lighting in my scene, once it has finished some of the textures my colleague has made appear to have black marks on them (but not when un-baked).
Is this an issue with how the textures were made or a unity issue?

It’s from the light source…
You have to change the Bias Or the Normal Bias Or Near Plane try to make it greater than 0.1