Bug with Arcs in Curves?

hi,

when joining curves with some arcs using the "join"-component, the resulting curve can't be internalised to a curve-component. See the attached file: the flower-like curve is joined to one closed curve. when using "internalise data" everything is ok, but after saving, closing and reopening the file the curve is gone. It's also gone when you copy/paste the component with the internalised data.

This error occurs with curves consisting more than one arc; curves with no or one arc are handled correctly.