I remembered from previous PT's you'd get in trouble if you didn't coddle up to the brats, but I didn't remember it was so hard to convince the tieflings of your good faith
To be fair, you don't really need to coddle up to them. Just help 1 of them and don't tell Mol off and they're fine. Anything else is just if you want to do it.
Also, why is the deception proficiencey bonus from cha not being counted in this roll ? That still looks buggy.
I don't know.
Without any logs regarding the roll and statuses regarding the party it's hard to say what or where the bug might be. (Whether it's specific to this particular dialogue interaction or something more generic)
From the information you've provided my gut instinct is asking "Did Wyll
actually make the roll?"
As from the context you provided, it is suggested that Guex confronting your party was a surprise. Meaning you didn't pre-organize your party to enter the dialogue. Then given that you cannot simply back out of this dialogue and re-engage it later. I wonder how you managed to "Let Wyll do the roll", when the game defaults to the Player Character in dialogues (Meaning your Durge would be the one doing the dialogue options and any skill checks) unless they're specifically positioned very far away when the dialogue is initiated.
Now THAT's a clue that totally escaped me. Fortunately, I have a save closeby, so I could do a replay .
I imagined Wyll did the talking because just before that , he traded with Dammon (being my highsest CHA) and then led on to pick up the next barrel of oil.
The combat log shows that it is indeed Tav that is accosted by Guex , not Wyll. You nailed it completely. (The cutscene shows only Guex, with his sword drawn , not the one he's talking to)
But here's another surprise. I wanted to doublecheck for the bonus, by ungrouping, sending the party away and let Wyll approach the barrel alone. Guex did not address him. Then I made Wyll talk to Guex, and he was friendly to him. No threats, no deception throw needed or threat of attack.
Now Wyll is an old friend of the grove of course. So I tried again with Lae'zel. Let her approach Guex solo. No reaction. Talked to him and he was friendly.
Finally I tested with Tav solo, and on approach, bang. Attack.
It is not every Tiefling's reaction though. As stated, the ones looking out on the rampart were grateful and happy to see Tav. Zevlor, Dammon, and the guy that oversaw the children sparring in the ring. They were releaved to see Tav.
Anyway thanks for taking the time to resolve this !