Rear inner fender crack

I was wondering if any body here other than me has ever had a crack in the driver side rear inner fender where the rear seat bracket is attached. Both of my XJ's have had this problem.

89 Laredo, 4.0, aw4, np242, d35, d30
90 limited, 4.0, aw4, np242, d35, d30

i have also had a crack in the passenger side on the 90 limited