Its not uncommon for them to snap cleanly especially in the case of a sudden downwards force, as the carbon is spirally wrapped it will create a shear point a bit like scoring glass. Breakages whilst playing a fish usually give rise to it splintering, I also believe that the carbon fibre also deteriorates over a period of time and becomes a bit more brittle will give rise to it snapping or cracking, At £20 for a replacement section it is probably not cost effective to have your section professionally repaired unless you live close to any repairers and can deliver it yourself.
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