I'm slightly surprised that the statement 2 posts above doesn't make reference to participation in the investigation by AAIB or similar. While it's certainly an incident in the context of an experimental flight permit or similar authorization, I seem to recall that agencies such as AAIB have participated in - and indeed led in some cases - investigations into accidents to test vehicles (and accepting the difference between accident and incident).
Also, with regard to the interesting piece in the post immediately above - and thanks for sharing it with us - there is a little bit of a difference between an accident or incident while conducting the tests where the element of exploring the unknown is present, and an accident or incident during a test flight but not when conducting a test point. While one might argue that the second ever landing is a "test point", it was stated that all planned tasks had been completed, so it seems it wasn't considered to be a "test". (Which may in itself be a topic for further discussion; at what point does a "routine" element of a flight on a flight test vehicle truly become "routine"?)