I find it a bit surprising. But looking at that sheet..
All of the below graphics basically are saying that there is a minimum curve radius around which the belt is designed to operate. It isn't about normal vs backward bends, its about minimum bend radius. The 2nd (do not crimp) and 3rd graphic images (minimum distance) are both describing minimum radius issues, but in the normal bending direction, not backwards bends (1st graphic). These belts are designed around minimum stretch fibers (carbon/kelvar/whatever) which when subjected to less than (tighter than) normal curvature is either stressing the fibers themselves or the interface between the fibers and the rest of the belt material resulting in an overall weakening of the belt.
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