What is the voltage, is it going through all stages of charging as required by the batteries?
Not enough information to know if you have a problem. My Magnum will raise the voltage and amps for bulk charging then absorb then float. When in float the voltage remains at float but the amps will change as the house loads are turned on/off, perhaps you are seeing this.
You could turn off the charger, use some battery power and see how that compares to past uses, charger back on and check the amps and voltage for charging.
Problem batteries can give strange results. Consider having them load tested at a good battery shop or perhaps even a auto store.
