System Information
Operating system: Win10
Blender Version
Broken: 2.91.2
Short description of error
Sometimes when opening a recovered autosave, the two windows of the project are not synchronized. There are only two windows open (no other copies of Blender), and changing the Active Workspace of the main window also changes the workspace of the second, so they are both definitely the same 'instance' of Blender and not two instances of the same save.
When moving through time or trying to animate objects, these changes are not made on the other window. The 'active camera view's do not align either. See video.
I don't recall experiencing this issue in previous Blender virions, but have had this issue four times on different projects.
Saving and re-opening fixes the problem.