At 8:06 of the first period in the Islanders/Flyers game, New York requested a Coach's Challenge to review whether a Philadelphia player interfered with New York goaltender Thomas Greiss prior to Radko Gudas' 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 Philadelphia Flyers.
Since the Coach's Challenge did not result in the original call being overturned, the New York Islanders forfeit their time-out.