Are you a new knitter? If you are then you may not know the person knitting in the video is knitting the knit stitches through the back loop which twists her stitches. I thought maybe she was knitting combined but she's purling normally so the stitches remain twisted. Not sure why you'd do that for a demonstration video.
Anyway, I'm not sure what's going on with your 3rd stitch, but some increases and decreases can show a little (or a lot). We have a whole section on increases at the video link at the top of the page if that helps.