Something in the updates was changed. Why?
Originally on version 2305 which had the startup options and the registry key for the option selected.
Updated to version 2306 - startup options gone and registry key gone
Stopped updates
Reverted back to version 2305 - startup options are there and registry key is there
I did not manually add the registry key - the revert to version 2305 added the key
Started updates
Updated to version 2307 -(which includes updating updates missed) - startup options gone BUT registry key set to Never value still there. This update did not remove the registry key as when it was updated to version 2306. This not deleting the registry key is different than the prior update.
Since updating I have not seen the "Outlook closed while you had items open. Reopen those items from your last session?” prompt at all and I have purposely left multiple items open upon closing Outlook. Outlook appears to be honoring the registry key settings and never prompting or opening left open items.