Are you on iOS or Android? Also, when you added the talks to the notebook, were you on iOS or Android?
What process did you use to add the talks to the notebook – did you select text and add that to a notebook, or did you use the share icon at the top of the page to add the full talk (iOS only)?
Are you able to see the talks you saved on LDS.org?
Are there a lot of items in the notebook? If there are not too many items to count easily – does the number of items you see in the notebook match the count that appears under the name of the notebook?
Is the notebook completely empty, or does it have other types of things, just not talks?
Do you have other notebooks, and were they affected?
Do you know if the data went missing at the time you were updated to Gospel Library 4, or did it happen some time after the update?
Samuel Bradshaw • If you desire to serve God, you are called to the work.