Originally Posted by
recursive
Does anyone know how something like this could happen? I'm not a mechanical expert, but I've never heard of a rear wheel coming out of position before.
It happens on occasion because....
Originally Posted by
recursive
Yes, the QR was closed tight.
... it wasn't closed tight enough.
Don't know what kind of skewers you got, but the boutique, super lightweight, external cam skewers tend to not clamp hard enough for some horizontal dropouts. Especially if they are chromed or stainless.
Basic Shimano or Campy skewers are far more reliable when they are closed correctly. The lever should get tight 90 degrees from the bike.