A common mistake back in the early days of Ethernet was to wire them as four sequential pairs, instead of the required (1-2) (3-6) (4-5) (7-8). This worked most of the time on 10BaseT networks, but would get flakey at 100Mbit.

If they got the pairs wrong at the wall jacks, there's not much you can do without repatching the whole thing. If they realized that they could make short cables that fixed it so that the pairs were mapped properly to port pins, that's quite clever in my books!