was Bug #768938 in launchpad
It is a workaround.
Gephi was relying on triangle counting for directed graph clustering computation. The definition of clustering for directed graph does not directly use triangles and thus computed values was wrong.
The algorithm used to count triangles was also not designed for directed graph.
The workaround is to use a brute force algorithm for directed graph and the faster one for non directed graph.
A nicer solution would be to find a good algorithm for directed graph, but I do not know one.
Fix issue 58
Thanks for the fix Thomas, it is merged now.