2005 Canadian penny error?

I was going through some pennies I found a few months ago, when I noticed I had this one penny that I couldn't date. I knew it was 2003 or later, since it had Elizabeth II's newer effigy on it, but there was too much grime and dirt covering the date. Figuring it not worth anything, I gave it a quick clean, uncovering the last two digits of the year: a zero and a five, but there's a circle seemingly bursting up from under the top part of the 5, making it look like a funky 9 or incomplete 8 number. Has anyone ever seen this before? Is it common?