I have not played S1, so can't confirm, but other players have confirmed that underhill ally is not working properly in S2. Upon summoning, the underhill ally should normally start buffing group members with health regen. Usually this doesn't happen unless you remain stationary for 5 to 10 seconds, ...

I can confirm the same. For some reason the companion will opt to go melee. Some toggles between passive and attack command seem to "fix" it.

Situation: I'm grouped as a nightshade and I'm stealth. Other group member pulls (aggro) a mob, and mob comes running. While the mob is not yet in range of the puller, every time when I'm within melee range of the mob, it will hit me, like I was not stealthed. It doesn't "see/uncover" me, ...

Location: Nisse Lair NPC in question: Tomte Shaman (level 12 ish) Bug: after being hit by the Tomte Shaman DoT, I was not able to cast any spells any more, each tick of the DoT would reset my spell casting timer. Attached image for reference. I was able to heal myself once, because I resisted 1 tick...