It's an easy solution, just get rid of the coach's challenge for offsides. The amount of times they're getting it wrong on review, defeats the whole purpose anyway. The inconsistency hasn't gone away, and it's increased the chances of impacting the game because they review so many of these plays.
Let Toronto keep reviewing every goal, and if it's blatantly offsides they'll be able to see it pretty quickly, and call the goal back before they drop the puck. They can even add an extra 15 seconds or so in between goal and puck drop to give Toronto more time.
Calling back a goal for being an inch or two offsides is a way bigger deal than allowing a goal because they were an inch or two offsides. That inch or two has essentially no impact at all on whether the goal was scored or not.