At 12:49 of the second period in the Flyers/Penguins game, Pittsburgh requested a Coach's Challenge to review whether Philadelphia's Valtteri Filppula interfered with Pittsburgh goaltender Matt Murray prior to his goal.
After reviewing all available replays and consulting with NHL Hockey Operations staff, the Referee determined that the actions of Pittsburgh's Ian Cole caused Filppula to contact Murray before the puck crossed the goal line. The decision was made in accordance with Note 2 of Rule 78.7 (ii) which states, in part, "that the goal on the ice should have been allowed because (ii) the attacking Player was pushed, shoved or fouled by a defending Player causing the attacking Player to come into contact with the goalkeeper."
Therefore the original call stands - good goal Philadelphia Flyers.
Since the Coach's Challenge did not result in the original call being overturned, the Pittsburgh Penguins forfeit their time-out.