Very cool. That may very well be what used to be called the "poor mans doubled die"... I'll leave that up to the real error guys. The true 55 doubled die is very distinctive. This is from my collection and there is no mistaking it.
The poor mans doubled die is just due to worn dies. They are not true doubled dies and even Wexler refers to worn dies as worthless doubling They have been hyped for many years. Please be aware that worn dies are not true errors even if dealers are charging a few dollars for them