On a single Calc worksheet page, nearly every hyperlink disappeared. All associated anchor text remained in place.
The worksheet is approximately 3500 filled rows under 40 named columns.
There were approximately 3000 links distributed in two columns. Perhaps 100 links remained in their original places.
It is unclear whether this event occurred while saving a version without exiting the program or when a file was saved/ closed/ reopened.
(Fortunately, several versions of the file were saved during the day when the disappearance occurred.)
LibreOffice 188.8.131.52 is running in an Win 7 Pro environment.
Please advise any thoughts about how to recover the missing links without having to hand replace each, and how to preclude this sort of loss in the future.