It is very common that a bookmaker starts its lines with basic coefficients which with time change. This is happening driven by different factors. Sometimes the situation about a certain match is changed: for example a key player gets injured. Or maybe a in-house information appears. Or sometimes the more players starts betting on an outcome the more the sportbook is decreasing the price for it to balance the lines. In any case the outcome with the dropping odds is an attractive opportunity to place a bet.