With less than 4 minutes left in the 1st period Corey Perry got tangled with Darcy Kuemper. On the play Perry's stick got tangled with Kuemper. With the referee standing right next to him Perry shoves Kuemper to try and get their stick free.
On the play the referee deemed like this soft push was called "roughing" by the referee. Marking this as one of the softest penalties of the playoffs.