Check the hinges for the bow. They have a notch on one side of them that allows the bow to sit properly when closed. If the hinge is installed backwards the bow pops out when closing up and causes the loose end of the bow to press against the canvass.
My 181e had that issue on one hinge. Once I identified the issue and reversed the hinge I am not having the issue anymore. However the original fix (by previous owner/dealer) to the canvass was to use something similar to Dacron Sail Repair Tape, which moved around to the point it bunched up around the corner and got in the way of the gasket when closing the bed. We are working on a solution with the dealer/canvas repair company to put a glued/sewed patch on the corner to reinforce.
Only issue we have had on an otherwise fantastic trailer and dealer experience.