I don't understand your question.
Can you describe it differently? Or maybe contact GTAC so that they can look at it with you?
the problem is not the simulation.
Since there is a collision and the collision is detected, simulation is doing its job.
You sized down the shank to 24.9 but the collision is far more bigger than 0.05mm so is still detected.
The problem is in the toolpath, there are lower contour profiles that remove more material than upper ones, causing the collision between the ipw and the tool shank.
You have to modify the toolpath to prevent the collision.
To better explain the point I've prepared this video:
have a nice day