The navigation system does not get instantiated on clients. UE4 4.8 adds a flag to navigation system that allows you to have proper navigation on clients, but in 4.7 it’s not possible without changes to NavigationSystem’s code.
Can you provide more info? What is the name of the flag? Where is it located? / What blueprint node is it found on? I have looked at NavMeshBoundVolume but there is nothing there that seems like a candidate for this flag?