There are many possible reasons for the rods breaking and without knowing anything about the rods that really can't be addressed, but then that was not your question.

One of the reasons for two piece graphite rods, when they first started making them, was to cut down on the number of ferrules as that is a weak point on rods. But, the companies have greatly increased the strength of the fittings and now the 4 or 5 or 6 piece rods are just as strong at the ferrules and do no negatively impact the performance of the cast.

Larry ---sagefisher---