Here’s what happens. I’m reading along in an imported lesson and I’m about 3/4 through, judging by the green progress line. I click on the arrow that usually takes me to the next sentence in the lesson, but instead flashes to a screen congratulating me for having finished the lesson. And then I can’t find any way to get back into the lesson, which means I’ve got all kinds of problems. Since what I’m reading is part of a novel, it’s not so easy to go back and find those 1,000 words that I’ve been cut off from. It’s happened again to me just now, which makes at least three times, all requiring about twenty minutes to recover from. I only have so much time in my day for Italian; I don 't want to waste it dealing with this problem over and over.
In fact, I can’t even get back into the lesson to see where I left off, which makes it much more difficult to replace the missing material.