Coinsandcanada.com

I am not normally one who pays much attention to errors in coins but this one really caught my eye as I was going through some change. It has a lovely raised edge that just touches the edge of all the writing and the date. Nothing different on the reverse though which is odd.

Any ideas on how it happened? Looks like it got stamped with the wrong tool but I am no expert in these things!

It's caused by either a coin rolling or wrapping machine.
Not uncommon and not an error.