Another common problem is the tile applied too soon on concrete dried less than three months. Look on the tile back for your answer. Glue didn't touch in spots on the floor?Too irregular floor and not enough thinset. Concrete surface pull off with the tile?
Thats spalling.
Tile cracked esp. on the edges of the tile and the room? Expansion problem as noted by others. The temp range is so small there should be no problem without a bad installation.Much tile work lives in the 80+degree range of differential temps., sometimes for thousands of years long before grout was invented.