The Green Bay Packers and Cincinnati Bengals both looked strong in Week 2. Green Bay picked up its first win by absolutely dismantling the Washington Redskins at home, while the Bengals dominated the division rival Pittsburgh Steelers en route to their first win.
In Week 3, the Bengals will host the Packers, and the lines have been divided thus far. According to OddsShark, the Bengals opened as narrow 1.5-point favorites, but the line has moved throughout the week. Some sites still have the Bengals as favorites, but most have shifted to Green Bay, with the Packers as high as 2.5-point favorites mid-week.
It's likely that oddsmakers consider the Packers the better team, but the home-field advantage factor from the Bengals accounts for a 3- or 4-point swing that throws everything into disarray. The over/under is set right around 48.5 points on most books.