This happens only with Bergger VC CB paper, as far as I know. Ilford and Kentmere (Arista) are my only other examples.
After I have tacked a piece of dry mount tissue to the back of the print, I cut the print ( and tissue) square all the way around with a rotory trimmer (yes it is sharp, and no I don't cut wire with it). As I crosscut the print (cut the short dimension), the last littlest piece of the corner tears off. Probably 1/32 inch (1mm) at most. I doesn't happen on the long cut, just the short dimension, so it has something to do with the grain. It is worse if I go fast. If I support the print or put something over it, no difference or worse.
Anybody else experience this? Have you fixed it? To date my only fix is to leave the last cut for the long dimension and to cut around the print 'backwards', i.e. using the factor edge of the paper as the true edge, not the newly cut edge.