Can you tell me the exact key sequence? The same bug is probably in all 4:3 screen cameras, but I can't reproduce it on 500D.
Immediately after loading ML via firmware update:
Switch to movie record mode
Record video
stop recording
hit playback button (the one above the trash button)
hit picture style, let the overlays load with the histogram on top, etc
half-press the shutter button to go back to live view
Strange thing is, I just tried that, then my battery ran out. I've just put in a new battery and tried it again, but now the overlay wouldn't get dropped like that. Although I've been having issues with the overlay gets dropped intermittently over the last few days. Usually I'd need to reflash.
I wonder if I missed something...
I've been using the HD_TA and CINESCO2 overlays if that helps....