If i get sewers, and I play a priest, I do not get the +2 coins for the card I trash with sewers.
Is this a bug, or did I miss something?
E.g.: game #18772354
What you are missing is that the trashing instruction on Priest is first and the +2$ for every future card trashed comes afterwards.
If you play another trasher after Priest, you can use Sewers to trash an additional card and also get the +2$.
To make this even more explicite, the trashing due to Sewers in this example happens between the parts
"Trash a card from your hand." and
"For the rest of this turn, when you trash a card, +$2."
from Priest. Since the second part hasn't happened yet when handling Sewers, you don't get the additional +$2.
I was convinced this was a bug as well. Even though I can grasp the explanation, I think it's very counter intuitive.
I guess reacting to the Priest trashing with Market Square and then trashing the gained Gold with Watchtower also doesn't trigger the +$2, right?
@markusin: Yes, that's also correct. Anything triggering from the initial Priest trash and causing an immediate additional trash (directly by Sewers or indirectly with Market Square/Watchtower) will be 'too early' for the Priest's second effect to notice.
As someone noted, due to the way Preview Kingdoms are made, this Priest/Sewers interaction will come up way less often once Renaissance is fully released. But of course it doesn't change the outcome of the interaction.