At 8:30 of the second period in the Panthers/Penguins game, Pittsburgh requested a Coach's Challenge to review whether a Florida player interfered with Pittsburgh goaltender Matt Murray prior to Jonathan Huberdeau's goal.

After reviewing all available replays and consulting with NHL Hockey Operations staff, the Referee confirmed no goaltender interference infractions occurred before the puck crossed the goal line.
Therefore the original call stands - good goal Florida Panthers.
Since the Coach's Challenge did not result in the original call being overturned, the Pittsburgh Penguins forfeit their time-out.