I have noted in another post recently that it is a frustration, annoyance even, to come to a lesson, struggle with a concept, and then find the same question arising often in Q and A. The Q&A section is often very long, and repetitive with a mix of highly relevant and less relevant comments (like this one in this section perhaps? - shrug), and reading all the way through it after every section, is not the most efficient use of study time. I suggest that when the urge arises to write in response to a question anything along the lines of 'this has been asked and answered before', that should signal the need for the question/answer to be directly addressed in the lesson - initially an addendum tagged in at the end of the lesson, but subsequently properly incorporated, for example. This is presented as an opportunity for improvement rather than just a criticism - as the end product will be much better lessons. Others may have other suggestions to address this and improve further.