Comment 7 for bug 190783

Right, I can confirm, too.
I think it is caused by Consolas having certain letters slightly wider or close to the horizontal advance space . If you look at the artifatcs, they seem to correspond to the fringes that fall outside the cursor while it is over the At sign, e.g.
With my font Pragmata, I see no artifacts. But when I select a proportional font with long swashes, I see even solid pixels of these remaining on screen.