Regarding my last post - a Revit 2020.1 Hot Fix is now posted.

Of specific interest...Autodesk writes:

Issues Resolved:
Fixed an issue that resulted in the loss of family data in some workshared models when family definitions had not been recently modified. This fix does not repair models which have encountered loss of family data, for more information refer to Family Corruption in Revit 2020.2

Click here to view the entire blog post.