The guarantees of the products generally concern wear and frost resistance; however, if cracks form in the toro element of outdoor tiles, it is clear that the installed product has been damaged due to a problem of installation or structural movements, which is very frequent in outdoor areas.
In outdoor laying, in fact, the layers often do not consider the movements to which an exterior is subject, both for the succession of the seasons and the inevitable changes in temperature, both for the seasoning of the base itself (where not always - because of the hurry of the contractor - are respected the timing of drying), and for the different movements to which the house and the surrounding outdoor floors are subject (especially in areas where the two structures meet).
Keep in mind that it has been calculated that on five lm of flooring the summer-winter movement makes this measure vary even by 4/5 mm. Therefore elastic joints should be created, for example, between the floor and the walls of the house; not everything should be left sealed and blocked, the floor must have a chance to counterbalance these movements. In addition, it is likely that the toro special piece was laid using glue in the horizontal part of the step, but the vertical part, in the rear area, was not filled: this could be the real reason for the breakage.
In this case, the installer should intervene as quickly as possible to avoid having to replace them all within a short period of time.