Machete sometimes fails to give hp/mana regeneration when fighting the dragon.

The machete is supposed to give you some health and mana regeneration whilst in combat with monsters, but since the last patch this does not appear to apply to the dragon. This is very irritating when your team has the enemy distracted and you're playing a jungler capable of sneaking a dragon. The buff worked normally last patch, but since 4.21 has sometimes failed to trigger.

Twice I have started to solo dragon at half mana with , only to find that the mana regen effect I was expecting does not occur, forcing me to flee when the dragon is at 1khp, unable to get that one last drain off.

Is this intended? The dragon is a monster, and should theoretically still trigger the machete buff, pretty sure this is a bug.

Edit: It doesn't sometimes fail, it never works. The machete buff procs when monsters autoattack you, and dragon's attack counts as a spell. No jungler receives the machete buff while fighting the dragon.