Edit: Though if it’s related to the “paging moves to known” feature, then you’ll have to mark unknown words manually until you catch all the words LingQ marked as known (turned white words) due to the “paging moves to known” feature that was on up until you turned it off.
Here are some additional replies/topics that I found related to a similar feature that you might want to know about, too (in case it’s helpful):
Finishing a Lesson (clicking the checkmark at the end of a lesson) marks all words within the lesson as “Known”: