Consider this graph, that I downloaded from the OpenConnectome project.
Graph[EdgeList[cElegans], DirectedEdges -> False] // DirectedGraphQ
Which makes no sense to me. Is there any logic to this or is this a Mathematica bug?
PS: The same thing happens with
SetProperty[Graph[EdgeList[cElegans]], DirectedEdges -> False] // DirectedGraphQ
edit: The original question was missing the call to
EdgeList. Sorry for the mistake.