Vaal Ruin disconnect and reset after host uses portal

My Vaal Ruin was ended prematurely while playing Co-Op with 1 person.

I had just witnessed the scene where the royal chamber is unlocked for the first time. I walked into the royal chambers with my co-op friend and they waited in that room as I used a portal to return to our stash for an item. The portal behind was closed when I exited and immediately attempting to rejoin my partner via a portal on their portrait gave me a message stating that the session had been disconnected.

Vaal Ruin charges are reset and the system is continuing as if the run was completed and failed.

I was playing as a Druid and my partner was a Monk.

Names:
Carimesi
HonkMonkMan