Hi,
when playing in a multiplayer party and one person starts a quest echo, only he gets the quest echo completed. Then the party has to do it again if the other person starts.
Can be reproduced.
It works correct on bosses or regular echoes, but not the quest echoes. Stability was enough for both, we tested it multiple times.
If it is intentional, then why does it work for quest echoes and not bosses or vice versa? At least keep it consistent 
Cheers,
Alexander