It's during the menus, during live, and during the playback, all set to Native. My HDMI didn't flicker, but the HDMI stopped working a week ago--likely due to the weight/angle of the connector (I haven't trying getting in there to solder it).
So I'm stuck with component until I fix it or buy an XL4 on sale today.
The unit also had started stuttering horribly and I replaced the HDD last week and it solved my pixelation problems.
Maybe put chokes on the component cables?