In the end, the officials gathered for several minutes to try to find conclusive evidence of the puck having crossed the line prior to the whistle. Due to the fact that the original call on the play was "no goal", the officials couldn't conclusively say that the puck had crossed the line under Bobrovsky's pad and therefore could not overturn the original call.
If the Leafs come up on the wrong side of this one, there's going to be a lot of talk about this one - especially because the puck can clearly be seen being fished out of the net. Many are of the thought process that this should have been ruled a continuation play, but the call has been made and there's nothing anyone can do about it now. Extremely unfortunate.