I, too, can't see any uneven cut. What I do see in the pic is the grass that must be a foot tall (bottom right in pic). Correct me if I'm wrong, you've got a newer model rider, 42" deck with 2-blade arrangement. Are you cutting or mulching? Given that your mower checks out as far as proper adjustment / maintenance, wear and tear, etc. I think that you're just pushing it too much...making it work harder than it can handle.