Welcome to irv2.
The house batteries will usually supply the 12v for control board of your refrigerator not the chassis engine batteries.
Here is a link explaining the power systems of your RV.
The
battery cut off switch has to be on at all times you use your coach to keep batteries fully charged.
The alternator while your driving and the shore power cord when camping.
If you have a bank of four house batteries and you had two changed, the other two, one of them maybe defective and is drawing down power of all four.
All four house batteries should have been changed so they were all the same type.
Here is a link to describe what may happen when changing battery systems out if not careful.