FlashXDR records files with weird frame-structure
 

It seems there is no problem during playback from XDR or with VLC, but if you analyse the frame-structure, you see the frames are totally mixed up. (i-frames, b-frames, p-frames)
My client is very unhappy, because it's impossible to edit them with avid.
MPG-recorded files are ok, 35mbit long-gop files are ok but long-gop or i-frame only with 50/100mbit or above are not.
This issue is new - i had a look at older files from this device and they are ok.
All files are .mxf and the camera is 1920x1080i50 (Toshiba IK-HD1)