I'm not seeing any flicker at all when voice becomes active and the top three lines become visible on 2245.On version _2245, in Display View, the top three lines flicker if I have "Clear on No Voice" checked. They do clear on no voice, but when a voice is present, they flicker.
EDIT: I do see the flicker. I didn't at first as the communications were so short but now that I've had some lengthier fire dispatches, the flicker is obvious.