You often find this with gates: the hardware is not mounted straight; screws are missing, or replaced by non-matching unsympathetic screws; even, as in this case, the hardware is wider than the post on which it is mounted. Here the carpenter shaved off the left-hand side of the post to match the bevels on three other sides. Yet someone has driven screws into the shaved edge rather than get a smaller latch which would make a better fit.
Canon EOS 30D + Chinon 55mm f/1.4 lens.