Yeah, I was surprised at how smooth it is in Chrome, Opera isn't bad either. I've added overflow: hidden on the body now, which stops the scrollbars appearing but I still get the glitch. It seems to happen more when the window is fullscreen but with the editor still showing (so in editor mode, not fullscreen mode). Might only be appearing at certain browser sizes?
The glitch itself is a brief appearance of the warped text on the left, it's just a frame or two, but it's quite apparent when it's there. I've attached a screenshot of what I see!
It looks like I've got something misplaced somewhere so it appears just before the animation starts?