When one adds BendPoints to Declare constraint arcs, these BendPoints are not saved in CPN 4.0.0. If one reloads the model, all bendpoints are gone and all arcs are drawn as straight lines.
BendPoints on normal imperative arcs are being saved, however. So this is a bug in the Declare constraint arcs only.
Tested in CPN 4.0.0 on both Windows 7 and 8.1.