Most likely the quality of the seal itself , poor quality rubber.
It’s not been chewed up when filter was fitted it’s the fuel that has eaten away at it , if you look closer it’s almost dissolved.
If you were running wvo or some rough quality biodiesel ie trace amounts of methanol in it then I would blame that as I have seen this on filters over the years on an old w124 I had that I ran on vegetable oil.
So I think poor quality rubber and obviously heat of the fuel has done the damage