In my 39 year career in industrial process control systems (maintenance, system design, teaching, and more), I ran into many precision gas regulators (usually controlling air pressure to precision values) that would not operate as we expected until we put a reservoir/accumulator on the output side of the regulator.
While this may not be needed on most generator applications, installing a fuel regulator with significant downstream volume would never hurt the performance and could be the solution to a lot of potential problems. I'd bet that the extra volume, if installed, would never be the cause of ragged operation.
I have one with 10' expansion loop. Every time the generator tries to start after lunch time on a sunny day, it fails due to pressure too high to open the FS 1. No problem early during the day. Can watch a pressure gauge go from 2 PSI to 5 PSI in 5 hours of direct sunlight. Even painted the exposed pipe silver to try and stop it.