I have a 2018 Windsport. Shore power charges house & chassis batteries at the same time or not at all. No charging happens if the storage switch has been tripped.
If the house battery is charging and the chassis is not, check your BIM (mounted on the frame behind the house battery compartment) - it is likely not working. A properly working BIM will sense that the house battery is receiving a charge and will connect to the chassis battery so the charge current will flow through. When not charging the BIM should isolate the two systems.