Please be aware that the Revit Team at Autodesk identified a defect in the 2020.2 update/build that is corrupting families in some projects.
On February 4, the team published the notification on Autodesk's Knowledge Network (AKN) along with four suggested workarounds. Here is the link to the article: Family Corruption in Revit 2020.2
The team anticipates delivering a hotfix to resolve this issue very soon. In the meantime, please take note of the workarounds in the above article should you encounter an issue in one of your projects.