If you choose Roche's path you meet Shilard Fitz Oesterlen in the Kaedweni camp. He asks you if you know anything about Triss' involvement in the Lodge and if you ask why he's interested in that he says that he just received a figurine and something like "even a witcher might not be indifferent to the beauty trapped within". It might not be exactly like that but it's pretty obvious he's talking about the figurine Triss is trapped inside of.

However, later on in Chapter 2 you get the scene where a bunch of Nilfgaardians are killed coming out of the fog and Roche says that he saw them carrying a figurine resembling Triss. It's contradictory because Shilard implied he already has Triss and if you follow Iorveth's path you find the figurine with Triss already inside of it (even though you don't know it), but she was at least put into the figurine before going through the fog. The thing she's trapped inside of looks nothing like her, so if she's inside of it Roche wouldn't have recognized her.

Maybe a Nilfgardian messenger says to Shilard "Triss is ours. We proceed with the plan".

I think the best explanation we have for this is that when you go on Iorveth's path everything plays out a little differently than when you go on Roche's path. It's sort of the butterfly effect in action.

The plot of the game is different based on your choices... do not mistake it with a different views on the same plot. So since you are talking about two different plots there, inconsistency is not really the case...

It would be like saying that the plot of Knights of the Old Republic is inconsistent between light side or dark side choices... the choices dictate and effect the plot... just so happens in Witcher 2 that effect is enormous

However, the OP is referring to an inconsistency within a single thread. Shilard seems to claim he has the figurine before the Nilfgaardians have been able to cross the mist with it.

The Nilfgaardian force seems not to be in possession of owl-post or homing pigeons, so even Shilard's knowledge of the successful capture and compression of Triss, and a fortiori his claimed possession of the figurine itself, appears to be a continuity error.

Is this then a plot inconsistency or out of sync conversation?
Trigger firing the conversation with Shilard too early and under the assumption that you have already crossed the mist?

The conversation with Shilard is triggered the first time you approach Henselt's tent. It's impossible to not have the conversation before going through the mist. It's not a big deal I was just wondering if I had missed something.

Here are the two scenes I mean if anyone wants to watch them

http://www.youtube.com/watch?v=F7-BTjZmah0#t=6m15s

http://www.youtube.com/watch?v=R7kdfVgULEU#t=12m45s

I played the first scene again tonight, and it looks like you're right - the scene definitely implies that Shilard already has the figurine, even though we know that he doesn't receive it until you're in the mist. And as you say, the meeting has to be before the mist.

Looks like they just changed their mind sometime about how it would play out, and missed changing one dialogue. That first one is fairly well buried in the coversation. With as many twists and turns as this game has, the biggest surprise is that there aren't more inconsistencies. :)

Could he be lying and trying to provoke Gerald?

He also might be relying on his people to do a competent job, they might have sent a messenger to say they were on the way and they had the figurine. It's not like he can track their iPhones and SMS them :)

He might well be bluffing. But I don't see how a messenger would have come through alive, without attracting attention.

Could they be using magic to pass a message, isn't one of the sorceress on Vergen side their spy?

Yes.

Fitz is trying to figure out where exactly Geralt stands in regards to Triss and how much Geralt knows. If Geralt already knew about the Triss/Figurine deal the shit would have proabably hit the fan right there and then when Fitz comes up with the "beauty entrapped within" smart ass line . Geralt knows nothing so he doesn't react one way or the other and all that Fitz learns is just that, that Geralt is out of the loop. Fitz tried to play him and it didn't work, but the did tried to play him and that opens the door for what he says being a half truth or a flat out lie depending on the interpretation of "was delivered to me"

The 'different paths different events' explains Roche's comment. If Geralt follows Roche's path the statuette, which is a likeness of Triss obviously, is carried across as is - thus Roche's comment and Geralt's leap to artifact compression, if Geralt follows Iorveth's path the statuette is carried across hidden within another statuette - the ugly looking thing Geralt picks up from the dead guy, the thing Fitz breaks on his table to get to the actual statuette inside - which explains why Geralt couldn't see the likeness.

Those would be my guesses anyway.

Yep, definitely a possibility as well.