Hi guys,
I‘m not sure whether that’s the best solution, but it worked for me: I turned off all offline notebooks and turned it on again one notebook at a time. I then noticed that the one single notebook wouldn‘t download. Again. Not good.
I opened the respective notebook in the regular way (not the „offline notebook setting). There was a very tiny green dot on the progress bar visible, which didn‘t move.
I then pulled down the notes liste until the spinning wheel appeared. After that the stuck notebook refreshed and finished downloading perfectly.
Maybe that could work for you too?