I just recently got to the Pious rank (150 favor) for the Silver Flame and went to retrieve my reward from the patron. However, when I asked for it nothing happened. No benefit was gained and nothing was in my inventory (checked all my bags just in case). So I asked for it again while having my inventory open and I saw something appear and it immediately disappeared before I could even get a good look at it. I'm assuming this is the thing I consume to get the blessing to increase the city regeneration rate, but it just doesn't stick around long enough for me to use it and I don't have any listed benefits from it.
I've also checked the regeneration rate by throwing myself off a lot of tall buildings and watching how fast the damage recovers and it's the same as it's always been.