Did that to a fire place door once, but I had overheated the thing like 7 times hehe. For real I like to stack them logs in there and get the thing read hot so that the brickwork gives off heat for a day or two after.
Heat cycling causes stress and eventually it goes pop especially if it was improperly installed and there is some type of load or pressure on it. We get the same deal with metallurgy and often times we give our workpieces a stress relief to let parts sort themselves out after machining or other. All normal and in a good days work. Funny how in JW land we used to think all these things were supernatural phenomena.
Also happens often on automotive glass where the body work flexes, loads the glass and on a cold morning you come outside to see one in a million pieces. Back glass often on account of defrost.