narrator confusion

I had watched season three online back in the fall and was happy that it was Mike narrating again.

I had pvrd season three in December (on discovery space) and am just getting to watch it now and the exact same episodes are narrated by some annoying guy! No mention of him on IMDb though...

Anyone know why this would have happened? Why have two different narrators for the same episodes? Of they replaced mike they're stupid, this guys not good at all.

For season four, just forget about this guy all together and stick with mike...