Occasional chain slipping/skipping - is it possible for the hub to be at fault?
Yes, the hub can be at fault. The freewheel mechanism pawls may be sticking in the retracted position, or the pawls and teeth are worn and the pawls are slipping out of the teeth.
You can try to confirm this by having a friend ride behind and to the right of you and watch the cassette area (in an area free of obstructions where you can do this safely). They should be able to see if the cassette spins when the slip happens. If it does the hub is at fault.