yes mention it- and is it on a curve?loop?
when it happens with me it's because i am looping- and make my upward (swoop) faster than the rest of that loop- i get skipped stitches with the fast swoop- i have to remind my self as going in to those motions to slow down-not speed up- it is really easy to get into a flow and even when drawing with a pencil you will notice in one direction you tend to (swoop) faster than with the rest of the design-- it takes a conscience effort to stay at the same speed (and practice)
she needs to be watching- consciencely slow down- and when she skips a few stitches- back up and go back over that space....and keep practicing.
there is certainly a learning curve- it all takes practice- but you have to pay attention to when things are not quite right- see what you are doing when it happens (trouble shoot) and find solutions- not just pass it off...and ignore it....especially if you are doing more than your own==your (practice pieces) should be where you identify those problems- and find answers--before moving onto someone elses masterpiece