At 5:30 of the second period in the Flames/Ducks game, Calgary requested a Coach's Challenge to review whether Anaheim was off-side before the puck entered the net.
After reviewing all available replays and consulting with NHL Hockey Operations staff, the Linesmen were inconclusive in determining whether the Ducks were 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 Calgary Flames forfeit their time-out.
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Coach's Challenge
1. A team may only request a Coach's Challenge to review the following scenarios:
a) "Off-Side" Play Leading to a Goal
A play that results in a "GOAL" call on the ice where the defending team asserts that the play should have been stopped by reason of an "Off-Side" infraction by the attacking team.
b) Scoring Plays Involving Potential "Interference on the Goalkeeper"
(i) A play that results in a "GOAL" call on the ice where the defending team asserts that the goal should have been disallowed due to "Interference on the Goalkeeper," as described in Rules 69.1, 69.3 and 69.4; or
(ii) A play that results in a "NO GOAL" call on the ice despite the puck having entered the net, where the on-ice Officials have determined that the attacking team was guilty of "Interference on the Goalkeeper" but where the attacking team asserts: (i) there was no actual contact of any kind initiated by an attacking Player with the goalkeeper; or (ii) the attacking Player was pushed, shoved, or fouled by a defending Player causing the attacking Player to come into contact with the goalkeeper; or (iii) the attacking Player's positioning within the goal crease did not impair the goalkeeper's ability to defend his goal and, in fact, had no discernible impact on the play.
2. A team may only request a Coach's Challenge if they have their time-out available and the Coach's Challenge must be effectively initiated prior to the resumption of play.
3. If the Coach's Challenge does not result in the original call on the ice being overturned, the team exercising such challenge will forfeit its time-out.
4. If the Coach's Challenge does result in the call on the ice being overturned, the team successfully exercising such challenge will retain its time-out.