Mis aligned die strike (if the reverse is normal.) If the reverse was also off, then it is off center and worth a little more. While it is an error, it's not really worth more than 50 cents. Unless the misalignment was more drastic. The double rim is cool, but that's all.
What they say Is true but, I have yet to find one Misaligned that much and would be thrilled to find this one.
Found this 1972 in the very next batch of coin. Looks to be the same misaligned die strike as the 1971 above.
Similar but not as dramatic. Notice how there is no raised rim on the north end of the 71 but you can still see the rim on the 72.
