Are both sets of batteries AGM? If you're mixing wet cell with AGM on the same charger, you'll need to make sure it supports both types.
It will probably need to be set for AGM as that lower charge voltage won't boil the AGM but it will still charge the wet cell.
I've been told not to mix them, but that isn't expert advice.
2019 Coachmen Mirada Select 37LS