This is not speculation, but rather observation. I don't know if it is the regen rate, of the NPC's resources have been capped but it is my observation that I'm getting far less from the NPC than I was getting earlier. I can even pin it down to between 5:00am and 6:21am that it happened. At 5:00am everything was normal. At 6:21am, the resources I was collecting was dropped by 10x and has been ever since. And that is from multiple cities, and it is unlikely that someone simultanously started farming the same cities at the same time in multiple seperate locations.
I repeat not speculatation, rather pure observation.

