As far as I understand it, the Brotherhood has control within the guidelines set by Igiss and within reason of what goes into Omicron 91. Of course we cant have the Odin sold on Rhodes, for example, but a ship already sold there should be kept there unless the owner of the system consents to its removal. This is much the same as things should not be added unless the owner of the system consents to its addition.
Distilled, the owner of Omicron 91 is the Brotherhood. The Brotherhood is led by effective dictatorship in Zelot.
Thus, the Osiris should not be removed from sale from Rhodes Shipyard in Omicron 91 without the permission of the Brotherhood, Zelot as it's leader in particular. Nor should any stealth updates carry this change without approval from the aforementioned.
I cannot speak for Zelot, but if I still led the Brotherhood, I'd not give consent for such a change to take place. The roleplay of the Brotherhood, her first flagship (Prox, now a base), second flagship (Altaneria, destroyed in RM/TBH war) and currently secondary (note the difference) assault battleship (Artemis), should not be dictated by forces outside her control.