Testing my group did yesterday showed that five people could trigger the conduit synergy from a single instance of lightning splash likewise with shackle from dragonknight standard all members of the group were able to trigger the syngery. I tested it later in the evening in Pve and a single person clicking the conduit made the synergy disappear for everyone else in the group.
No clue if this was one more thing done in the patch that wasn't added to the note's or it's a bug either way I wanted players to be aware.