You may encounter this warning when you open a workshared cloud model.
Warning: You made changes that have not been synchronized for an extended period of time.
Issue: When you open a workshared cloud model, Revit implicitly updates the local model to make sure you are working with the latest changes. However, this implicit update will not occur if the local model includes any changes that have not been synchronized with the central model. In this case, the local model becomes out of date with the central model.
You can continue to use Revit Cloud Worksharing to work on an out-of-date model. However, if the local model remains out of date for an extended period of time, the editing will be limited to the elements and worksets you currently own.
You can work on an out-of-date model, but you won't be able to check out or edit any elements or worksets that you don't already own until you Reload Latest or Synchronize with Central. This restriction ensures better performance of worksharing operations and more effective multiple-user collaboration on the central model.