We bought a 1994 Coleman Rio Grande last year with the original Magnetek 6409 converter and I have a question if its operation correctly.

We have only dry camped with it, (which is what we plan on doing for the most part) running everything off two deepcycle batteries and an inverter as well as 12 volts for the lighting through the converter on the battery setting. That works fine.
While recently adding some additional 12 volt outlets I just happened to notice that when plugged into shore power at home, the 120v ac outlets are powered regardless if the switch is set to convert, off or battery. Is this normal operation?

Thanks - Brian