It may be that the two statements from the RAFM website are not connected, or is inaccurate in detail.
Note also that the RAFM mentions a Halberstadt C-type, and not a DFW.
GB3 consisted of VB 107, 108 & 109: ll Voisin units at this time.
Le Verrier was taken prisoner, and Lattard died of wounds in a German hospital.
If this was the first German aerial victory, it is a significant event, yet I can’t seem to find a source that gives me Kastner’s unit, let alone that of the other aircraft involved in the combat.