I really wish you could carry more than one SIVA Offering. When I'm sitting on a single Perfected Offering, I have no choice but to wait idle, and hope for other players to appear in the Forge at some point. Whereas with a Fused one, I can play it by myself while waiting for others to arrive. The only problem is, that after using the Fused Offering, I don't have any more left, and have to either find a quarantine patrol, or go back to social space to fetch another from the vault. It's just a very poorly implemented system in its current state. Especially when you can carry several Court of Oryx runes, and use the Reciprocal ones to attract other players. That's exactly what I did last night, and managed to lure three other players there, when I played it solo for a while. It's also beyond me, why you can't see there's people playing the Forge from the Archon's Keep outer area, like you do in the Dreadnought's Hall of Souls.
EDIT: The Shiro quest mark bug still remains unfixed for me as well.