Cross ports normally fray over time. Particularly in the curve at the corners, where fibres are less supported by their neighbours so to speak. My impression from inspecting canopies is that end cell crossports tend to fray the most, with center cell ones next most common.
But the corner fraying should still be within the 'box' formed by the sides of the often rectangular cross ports. (On modern canopies that is -- older ones had round cross ports more often.)
Actual tearing beyond just fuzzy edges would be a concern though.