Finder sidebar: drag iCloud Documents to Favorites appears to break Documents (Click does nothing)

macOS Monterey 12.0.1 - Mac mini wiped, macOS fresh install.

Everything was working fine: iCloud Documents is enabled and is displayed in the Finder window and sidebar. Then, in the sidebar, I dragged Documents from the iCloud section to the Favorites section.

Now, clicking Documents in Favorites does nothing. Documents is selected in the sidebar, but the location in the main Finder panel does not change. For example, if I'm in my home folder, and in my sidebar I click Documents (which I moved to Favorites from iCloud), the Finder panel stays on my home folder. If I enable Finder's path bar, I see "[iCloud Drive Icon] iCloud Drive > [Folder Icon]" — that is to say, "Documents" does not appear in the path.

Clicking Documents in the Finder main panel displays the "iCloud for Documents You can move your existing documents to iCloud by dragging them here from the Finder or other apps." message. Navigating to Documents this way does not display any files, and does not highlight Documents in the sidebar.

My documents are definitely in my iCloud Documents folder. I know this because if I set my Finder view to List, I can expand my iCloud Documents folder and see (and navigate into) the subfolders there. In fact, Finder's path bar shows "[iCloud Drive Icon] iCloud Drive > [Folder Icon] Documents > [Folder Icon] My subfolder"

Undoing or resetting changes does not revert the problem. I dragged the Documents link from the sidebar Favorites section back to the iCloud section, but my iCloud Documents folder still does not behave. I Used Finder > Preferences > Sidebar to show and hide iCloud Documents but the folder still does not behave.

When I disable iCloud Documents sync, my iCloud Documents folder behaves, but my local Documents folder still does not. This would imply that the initial act of dragging Documents away from the iCloud section to the Favorites section in the Finder sidebar breaks the local Documents folder. When iCloud Documents sync is enabled, the symbolic link between the local Documents folder and the iCloud Documents folder causes the problem to carry over to iCloud Documents.

Get info shows two unusual things:

1. Size is stuck at 'Calculating Size'
2. Name & Extension textbox is editable. If I attempt to change the name of the Documents folder here, Finder throws the error "An unexpected error occurred (error code -8072). An 8072 error usually indicates a permissions problem. However, Get info clearly shows my account has Read & Write access to the local Documents folder.

Welp, the final step is to restart my Mac. Let's see what happens! (follow-up coming after restart)