Cylinders on separate sides of 5th wheel??
Reason I ask and say 5th wheel is because of the 2 regulators
Do you have problems with both cylinders (Low pressure/fluttering etc)
OR when using cylinder with the RED regulator?
Red regulator is a single stage 30# reg used to drop cylinder pressure prior to feed it across front of rig to the 2 stage reg that feeds rv propane system.
The 2 stage reg is what maintains the 11" WC (0.4#)
IF issues are when using 'off side' cylinder (the one with Red reg) then swap cylinders (or just use the one at main reg (where change over valve is)
Red regulators routinely have been a problem