Why is "Duty Roulette" a solo feature?

[Taekrys]

Source: here.

Thanks a lot.
And I think that answer indirectly to my question: they did not care for solo or group, they just COULDN'T put the feature for pre-formed group yet (even if I don't really get why, but nevermind).
So that goes for every of anyone else's statement and means that this was not to "counter" anything or anyone, but just accidental.