If Verona manage to hold Inter to a draw in this match then yes, it will be a bad sign for Inter because in the previous match Inter also only drew 1-1 against Genoa. But yes, with Henry's failure to take the penalty kick, it was bad luck for Henry and Verona but for Inter, Henry's penalty kick failure was a stroke of luck.
Because yes, the penalty occurred at the end of the match and of course if for example Henry managed to make a goal from the penalty kick, then the match would also end. Unfortunately, Henry failed to do so, leaving Verona to settle in the relegation zone at this moment but for Inter, clearly remaining strong at the top of Serie A standings at this moment.
Inter Milan did manage to win the match after all but it was harder for them than it should have been. These signs are not good for Inter Milan considering they have very tough matches coming up. They need to perform better. If they want to get further in the Uefa Champions League or get the title they need to start performing better. I mean scoring the winner in the extra time of the 2nd half just cannot be acceptable.
Anyway, a win is a win but I think it is starting to get tough for them to keep the lead.