I am posting this as an FYI in case anyone else ran into this issue.
On my Vero 4K I use systemd to auto-mount a SMB share from the Ubuntu 20.04 server on which I keep all of my media. But after the September update I got the “this item no longer exists” message when trying to play anything on the Vero because the auto-mount stopped working.
After much trial and error, it turns out that the vers=3.11
option, which was needed to make the automount work properly before the update needs to be changed to vers=2.0
for it to work after the update.
I have no idea why this fix worked, but if anyone finds their SMB mounts breaking, perhaps this will help.