I find it odd too. This happens all the time though, which is why I often discount people who try to read into the "steam" as if there's some smart money out there who is in on a fix or who knows better than me or some perfect efficiency of the market as an aggregate which a smart bettor can use to try to deduce who is likely to win based on how the line moves. You can't even blame Australian money betting Matthews as they aren't allowed to wager at 5D or BM and other popular sportsbooks that many of us use in North America or Europe.