Apple TV2 and Infuse

AppleTV2 Infuse, in grid mode, is showing some Incomplete video pics. However all metadata information have been loaded correctly. my video files are in m4v format and can be red with no problem.
There has been No change after a reboot, when trying to reload the metadata or after a reset.
I’m using last version of firecore
Can you help ?
Anyone else with the same problem ?
Thank you