[Gameplay] Baron "level-ing up" while fighting

I'm not sure if this is a bug or not - I do remember some time ago that Meteos lost a dragon in LCS because it leveled up right as he smited and he no longer had the damage to take it. Caster pointed it out and a patch or two later it was fixed (or I believe that is the case). However, this is not the case with Baron. In a game I was just in, I had smite ready at 780, cast it as I saw Nashor fall to 708 (at the 28:00 minute mark), and then he levels up to 897 HP (at the 28:01 minute mark) and we lose the Nashor.

Not that this is a "bad beats" story, but my understanding is that epic monsters leveling up in the middle of taking them is no longer an intended game feature. If that is the case, may want to look into it. I don't have a clip but I do have the replay if needed - but I'm sure you can replicate yourself in a game as well.

Edit: also as a side note - I went to report this under the "report a bug" feature in the client, but the button didn't do anything. It's immensely tilting for the "report a bug" button to itself be bugged out.