Party Scaling QUESTION

Hello couldn't find anything about this!

How does party scaling work? When do monsters become stronger? Every time I join the AREA of my friend or when I Join the Party itself? Does it auto adjust every time I leave the AREA? Please answer.

I was wondering about that too... Yesterday, I went to help a friend in Act 2, and a boss I usually defeat in 1-2 minutes suddenly turned into a god! The creature was stronger than any other boss I’ve ever faced, completely unbalanced

I’ve only been able to play Act 1, so I can only speak for that. But my experience has been exactly the opposite. PoE2 seems much, much easier in a two-player group versus playing solo. Boss encounters have taken a fraction of the time in multiplayer, and compared to running solo I never really feel at risk of dying when in a group of just two. I feel like the multiplayer scaling is way undertuned and makes it feel like an easy-mode. At least for Act 1.

Sam experience for 2 players party, the game seems much to easy in 2

Can someone describe how the party scaling actually works? I soloed a boss easily (in Act 2), but when I tried it when in a 2-person party, I got one-shot and died without even seeing what hit me. Not sure if this was just a fluke or if boss damage scales when in a party. Can anyone confirm? If the boss damage does scale, then it just seems like a stupid game design to make me never want to play with my friends.

Shit gets more hp (think its 100% more)
and drops more shit (feels like 50-80%ish more)