Looking at the update post it's stated that "Uniques have a 1/43 chance of dropping, and only one player can receive a unique per fight." So it is indeed intentional and currently impossible for a double drop to happen.
Comparing this to the OSRS Wiki which states that "There is an effective 1 in 43 chance of rolling the unique drop table per kill. It is possible to receive multiple unique drops per kill with multiple players, which is calculated based on the number of players and their individual contributions toward the kill." I do think damage should also matter as currently there are some players doing the boss in relatively unprepared gear, which as much as you're happy for them it feels like a bit of a pisstake when they get a drop doing half the damage everyone else did. But we don't need to get into that as that's not what the suggestion is about.
Full support from me