So, a Rogue's sneak attack can only be used once per *turn.* It does not say round, so the Rogue uses their sneak attack feature on their first attack that hits an enemy, and when their *turn* ends, a new turn begins, thus they can apply sneak attack damage to opportunity attacks.
Also, it says flat out that if the Rogue has advantage on their attack roll, they can sneak attack. *Then* it goes on to say that they don't need advantage if 1) an enemy of the target that isn't incapacitated is within 5ft of the target. And 2) the Rogue does not have disadvantage on their attack roll. That second part only applies if the Rogue does not have advantage, so am I wrong in thinking that even if a rogue would have disadvantage from something, so long as they have advantage as well, they can still use sneak attack, since they technically still have advantage, and thus the second part about disadvantage being a disqualifier doesn't apply? Extremely pertinent for BG3, I feel, since you get advantage for attacks for simply breathing within 10km of an enemy.
Also yes, sneak attack dice are bugged and not increasing to their proper values. Noticed that on my second character, when I actually used Astarion in my party.
