I picked this one up at a very fair price. I think people are underestimating how rare the modern Winnipeg produced errors like this (which are not back door jobs) actually are. Hard to believe this coin actually fits into a plastic mint roll tube (which it does). The lip on the obverse sticks way up, but without any design. Perhaps the second strike by the reverse die (hammer die) was done with the coin sitting on the collar? Enjoy!
No, the coin did not eject properly and a blank planchet sat properly in the striking chamber with this one just barely overlapping it. Now, to find the matching coin - the one struck through this overlap - would be really cool.
That is how I imagine it happened and was also thinking about the other coin, then read your next post