It seems to be an issue with the UVs generated / imported that is causing the bleeding on shadow casting which is still causing problems in some situations? There was a change from Unity 4 to Unity 5 with how this works.
Try to set cast shadows in your mesh renderer component to two sided. Then the Shadow Bias to 0.04 and Normal Bias 0.05.
Maybe try to post in Unity forum about this too. It's not necessarily a Qubicle issue.