I import a book into LINGQ. The system divides the book into lessons. I read on my iPad. When I finish a lesson and go to the next one, it happens regularly (but not always), that the text of the new lesson does not appear. I then have to close my iPad, open him again, open LINGQ, click on the lesson. Then the text appears, but there is also a pop-up saying:

App is offline. Showing cached lesson data. Refresh the lesson to see the latest version .

This is of course rather annoying. It did not happen in the past. Can anything be done about it?