Why don't all electrical plugs work on inverter only??

My Holiday Rambler Neptune is wired in such a way that I must be either on generator or shore power to get all of my electrical outlets to work. One outlet that closest to the bed won't work unless we either have the generator running or we're plugged into shore power. That means that if we want to plug something in when only the inverter is on, we have to run an extension cord to one of the other outlets that works without needing to be on generator or shore power. To make dry camping a little easier in the future, I'm thinking of rewiring the outlets so all of them will work without needing to have the generator on or being plugged into shore power. However, before I start rewiring I thought I'd better find out from all of you as to why you think the RV manufacturer didn't want all of the outlets running off the house batteries via the inverter without generator or shore power. The only justification that I can think of is if the RV manufacturer didn't want you draining the house batteries too low. Any other reason??