On the inside you can see the razor sharp flakes of glaze that have already fallen off the outside of this test piece. They reveal that the clear glaze, which looks fine on the inside, is under too much compression. The weaker interface between the slip under layer and the body provides a point of failure. This reminds us of the morality of making pottery, we have a responsibility to make safe ware.
Ask the right questions to analyse the real cause of glaze shivering. Do not just treat the symptoms, the real cause is thermal expansion mismatch with the body.