Council of Elrond

this came up at Worlds over the weekend.

Snaga-hai writes:

Playable at any tapped or untapped Shadow-hold if the influence check is greater than 9. Once in play, the number required to influence this faction is zero.

question: does "this faction" refer to the copy of Snaga-hai in question, or to any copy of Snaga-hai?
in other words: if one Snaga-hai is in play, any influence attempt against your own copies of Snaga-hai requires a roll of 0+?

It applies to only the card in play.

This is because the card in your hand contains the exact same text, which means that the number can only go to 0 for that card once it is in play, as well.

Personally I fully agree.
But if that is so, then I was robbed of a victory (and a place in the finals), but there were some very experienced players present who ruled otherwise, so is there really no hint of controversy here?

In multiplayer game two players have one copy of Snaga-hai in play each. If third player want to influence away Snaga-hai of one of his opponents, he must specify whether he is influencing this faction (of player A), or this faction (of player B); mere declaration My character is trying to influence away Snaga-hai is not unambiguous.

Like in case of unique faction where distinction between between "influencing a faction X" and "influencing a particular copy of faction X" is insignificant, in case of multiple copies of the same non-unique faction in play belonging to different players the distinction is essential (whose unused GI will be subtracted from check, which copy will be eventually discarded).
It is also essential due to cards like Tribute Garnered, or One Dear To You (also in two-player games), which are played on particular copy of faction, not "on named faction".

I thought all controversies died when the NetRep did.

Multiple copies of Deep Mines are not the same site.

Multiple copies of non-unique characters are not the same character.

Multiple copies of a faction are not the same faction.

See also Hour of Need. "This faction" refers to a single faction, even if there are multiple non-unique factions by that name in play.

See also Barrow Blade: "play this with the Dagger" does not mean that all copies of Barrow Blade are played with the Dagger.

I don't know if this is relevant:

Annotation 1: A card is not in play until it is resolved in its chain of effects.

In situation in question at least one copy of Snaga-hai is already in play.