<Paul> AGREED, AGREED, AGREED
I would be very surprised if the glass delamination problem is related to torsional stress from driving with the top closed. Ferrari has a long history of glass delamination problems that has been present through several different glass suppliers.
I am not directly aware of why it does delaminate but can say from direct knowledge that in the case of the Testarossa back glass being prone to stress breakage it was because Ferrari went against a direct recommendation of the glass supplier in the glass specification. Ferrari insisted because the glass design improvement would have cost a few more dollars per unit and they didn't want to spend it.