Sorry to nitpick here as well, but the "nuns" in question are not nuns. They are female householders.
All vinayaesque ordained (as opposed to tantresque ordained) Tibetans are ordained by the Sarvastivada system, and in that system, no lineage of nuns were transmitted into Tibet from India. Therefore there are no Sarvstivada Nuns, or no "Tibetan nuns".
They might be worthy practitioners, or worthy shugden-bashers, but nuns they are not. They might be afforded the status of being a nun, by their supporting communities, but there is no point in holding them up to the Vinaya as that has nothing to do with them, their being householders.