Can you post some screenshots presenting the issue, with navmesh drawing enabled?
My hunch tells me projection succeeds but you get different location that you expect. Is there navmesh on top of that unreachable thing player is standing on top of? 
Can you post some screenshots presenting the issue, with navmesh drawing enabled?
My hunch tells me projection succeeds but you get different location that you expect. Is there navmesh on top of that unreachable thing player is standing on top of?