Well, I'm noticing that you used the phrase "appears to be happy" twice in your post. Some kids are kind of quiet and compliant by nature, and aren't going to express their dissatisfaction in any direct way. It is possible that the "hard" comments are a quiet complaint of some kind. Possibly, there are some 2e issues that are in fact making the work hard. Maybe most likely, however, is the possibility that she is dumbing herself down to fit in. If the work is so far beneath her level that it is confusing and/or demoralizing to her to be asked to do it, then she might be choosing to act as if it is hard to be "normal."
We have always homeschooled, but I think my daughter might have looked like this in school. I think she would have "gone underground" very easily rather than have made any loud noise if she were unhappy.
