Check to make sure the cotter pin on the stub axle is tucked in nice and tight within the perimeter of the axle nut. If it is hanging out to far on either end it will interfere with the hub turning in either direction.
I have had that happen on several occasions.
FWIW I keep my hubs locked pretty much 100% of the time. Unlocked hubs will not allow you to have any oil splashed up onto your railco bushing. If you don't like that, at least make sure to ride around with them locked on the weekends.