I found this today while removing some used PNCs from paper. At first glance, I thought the light blue plate number was missing, perhaps a plate hopper. On closer examination, I found that the light blue color was offset to the right and the darker blue plate number printed over the top of the light blue.

The scan shows a properly lined up V2111 on the left, the offset stamp with red ovals highlighting the offset, and the unmodified offset V1 11 on the right side.

Has anyone seen something like this before? Are they uncommon? Any information would be appreciated.
Thanks,
Scott