Passing through impassible objects

If this bug is already known, please link me to the thread where it was reported.

One of my friends got beta access and I decided to postpone my progression, so we could play together.
When he reached Forest Encampment on Cruel, I decided to "drag" him through Act2 so we could play on Ruthless as soon as possible.
The bug: when one person has a quest, that involves removing roadblocks, completed, and other person have this quest incompleted...well, check the screenshot:

He could also see me running through impassable spikes at Western Forest.

"

Rhys wrote:

We want every player to open the Ancient Seal individually, because it's important for the plot. This means that it needs to be different for everyone. So, if one person opens it, and the second person doesn't, then they will see conflicting versions of it.

Most of the time this is fine, but as you discovered there is some weirdness possible. There isn't really a way to fix it, though.

Well, you can use same approach as bandits fights in act2:
Lets say that a mixed party of people who activated the seal and the ones who didn't activate it yet reach the location with Ancient Seal.
1) Someone from party creates new instance of location with Ancient Seal.
2) Server checks the whole party and sees that someone didn't active the Seal yet.
3) Server sends special message to the players who already have this quest completed - they will see "old" version of location with Seal (or any other roadblock) still intanct, but they cant activate it! They will have to wait for all the players who didn't yet activated the Ancient Seal to activate it.
4) When someone who already activated Seal attempts to activate it again, he receives a message "The following players must activate the seal: <names here>".
5) When all of players activate the Seal, the way becomes clear.