At 8:14 of the first period in the Ducks/Lightning game, Tampa Bay requested a Coach's Challenge to review whether Anaheim was off-side before Brandon Montour's goal.
After reviewing all available replays and consulting with the linesman, NHL Hockey Operations staff was inconclusive in determining whether Anaheim was off-side prior to the goal. According to Rule 78.7, "If a review is not conclusive and/or there is any doubt whatsoever as to whether the call on the ice was correct, the On-Ice Official(s) will be instructed to confirm their original call."
Therefore the original call stands - good goal Anaheim Ducks.
Since the Coach's Challenge did not result in the original call being overturned, the Tampa Bay Lightning forfeit their time-out.