For me, it is duifficult to tell where the crack is from the photo.
Can you tell us the material? I am assuming it is something that does not take well to fast cooling cycles that cause built in stress. Of course it could be a tool design problem where there is insufficient clearance to remove a brittle part, which is why the warmer tool doesn't cause a crack.
Did the part ever run well?
email: louis AT plastics DOT com.
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