Shurflo 4008 Revolution rapid cycling

We just used our new-to-us 2011 Outdoors RV Back Country trailer this past week, and noticed that the Shurflo unit stutters like a machine gun when the faucets are opened to a low flow. The stuttering goes away when the faucet is cranked open to near max flow. Checked for leaks, cleaned the aerators, cleaned the strainer on the pump inlet...no changes. My old trailer had an older Shurflo that had an adjustment screw, but I see this one has a bypass adjustment screw (allen key) but not sure if I want to tinker with that or not? Otherwise everything works fine.....perhaps it's something I should ignore and not worry about, but curious as to solutions? Pluming lines are 1/2" PEX or similar poly.