Ah, then it doesn't count
. But thanks for giving it a shot.
Seriously, that extra bit of circuitry may be holding the video output signal at a set state until the next time it is changed, but if so then it represents an unexpected 'cure' for the jail-bar problem even if you never intend to use the inverse-character feature. I would find those very faint vertical lines perfectly tolerable.
I also note that your VDU seems to be RF-connected so the resulting modulated then demodulated picture will be less hard edged than the one you would get via a direct composite connection.