We had the WDAZ broadcast on in the press box. They showed the the replay from directly above several times in slow motion. It looked as if the puck hit the crossbar near the corner, deflected slightly downward, hit the post and bounced out. Nobody in the press box thought it was a goal. We were surprised when Mason said it was.
The reason the puck wasn't dropped immediately was because Mason talked to the goal judge and the ARs, which he is allowed to do.
Video replays are not used during the regular season. If they were, I am confident that the goal would have been waved off.