I believe the 722 suffered the same issue at one point. When you'd hit digital 0/over, it would invert the signal instead of the "table top" look. They fixed it in firmware:
1.67
fixed - bad overload behavior from 1.60 fixed
fixed - CF no longer erroneously shows "full" after deleting files and emptying trash with a Mac
fixed - time remaining now changes properly with ext word clock
fixed - linked units now advance take simultaneously with file split
fixed - user bits now properly track take number on both hard drive and compact flash
changed - FireWire screen now says "...don't disconnect firewire cable..."
added - upon update, it now prompts the user to update the date/time
released March 24, 1006