Very high tris in unity 2017.1

Unity Engine
1

I have a scene that in Unity 5.5.0f3 it had 178K tris at a specific camera angle.
After updating to 2017.1 the camera (having not been moved) shows 40.8M tris.
Lights have been re-baked.
What might be causing this?

Brian

2

Try using the frame debugger to see what is causing it.