Passive: Jungler broken
Being in combat, as per the tooltip, does not grant you the HP or Mana regen buff. You only gain it when taking damage from the camp.
I assume this is a bug, given the "in combat" wording.
Even if not, this is a gigantic buff to junglers that blindly auto camps in melee range and / or use point blank spells, rather than having to actively kite the camps. This further limits the pool of viable junglers (massively down on S4 jungle), and serves to make the junglers that were already most problematic / strong even more powerful, relatively speaking (WW, Lee, Rengar, Amumu, Rammus).
I feel like both this and the lack of jungle xp / gold and dragon / baron gold has drastically cut the list of viable junglers, and made the strong even stronger ... the so called "strategic diversity" promised has so far resulted in the exact opposite.