Normal?

Hello,

I have been riding my Brompton for over a year now. Been through rough road, bumpy brick road and humps. When I folded it this morning I noticed that there’s uneveness in wear of main frame hinges.

Now, I maybe wrong but I remember having higher bump when I felt it unlike today it feels almost flat. Is it because all the load are on the top instead of split pressure between the two parts?

Thanks for the answer.