What is causing these texture artifacts, seen on device since switching to Unity 5

Please see the image attached. The black, white and yellow artifacts are visible on the IOS (iPad) shots on the right of the image.
This only started happening after we switched to Unity 5.
They don’t appear in the editor/PC Version of the game.
There appears to be no real consistency as to when or where these artifacts appear. It seems to differ from build to build.
The only consistent aspect we can see is that it only ever appears on scene geometry which leads us to believe that it may be something to do with the light maps perhaps?

I resolved this issue by re-exporting the from maya and re-importing the meshes that appeared broken. Seems obvious, but I hadn’t originally considered this as a solution as the meshes looked fine on the PC version, only a selected few appeared broken on the iOS and the problem only occurred after switching to unity 5, so was approaching solutions from that angle.