B- I run all water off the pump also. When I installed the Vagabond RO system, I noticed the pump cycling every few seconds. My coach has two diverter valves: City/Tank-Fill and Filter/Filter-Bypass. incoming water goes thru hose connection, then F/FB valve then C/TF valve. The cheap compression type bypass valves leak internally, allowing house pressure to escape around the valve stop inside the valve housing. I installed a John Guest 1/2" o.d. check valve between the two valves and it cut my pump cycling to a minimal amount (maybe every 8 minutes it bumps a few times). I still have one of these buggers leaking someplace, but it is a small nuisance now, and all internal. Sounds like you may have a larger leak causing pump to run past its duty cycle.
You can get the JGuest valves online or in a well stocked plumbery, or you can get a brass body check valve under the SharkBite
brand name at HD or Lowes. I had to get some 90 degree bends & coupling and a short length of pipe to make a goose neck assembly to fit the check valve into the tight pipe matrix behind the utility panel to make it fit neatly. Hope this helps.