Sims stops writing/resume books

Have been experiencing this a lot the last...year(s)? Sometimes I think it's connected to the title and description of the book, but not really seeming to matter today when two sims are trying to finish their books. Sometimes it helps keeping that sim active, but not always it seems today. The "progress circle" on the interaction goes to full in a second and they rise without writing, or write a shoooort while and then I find them doing something else. It's been like this for many different sims no matter which save or household.