Not sure if it was 9805 or 9807, but aliases no longer seem to work. This surfaced with a local alias that another local user has been using with success for some time. 

10:16:08.167 [20251065] alias:abuse@mydomain.com is an alias. Expanding recipient list.
10:16:08.169 [20251065] Delivery started for me@mydomain at 10:16:08 AM
10:16:08.169 [20251065] Removing Spool message: Killed: False, Failed: False, Finished: True
10:16:08.169 [20251065] Failed to generate bounce message for empty alias.
10:16:08.169 [20251065] Delivery finished for me@mydomain.com at 10:16:08 AM    [id:20251065]

Looked into it a little more, and that abuse alias can receive email from another domain, just not locally:

11:35:42.086 [20251071] alias:abuse@mydomain.com is an alias. Expanding recipient list.
11:35:42.089 [20251071] Delivery started for me@otherdomain.com (via bypass - SMTP auth bypass) at 11:35:42 AM
11:35:45.095 [20251071] Added to SpamCheckQueue (1 queued; 0/30 processing)
11:35:45.095 [20251071] [SpamCheckQueue] Begin Processing (priority Normal).
11:35:45.096 [20251071] Blocked Sender Checks started.
11:35:45.096 [20251071] Blocked Sender Checks completed.
11:35:45.141 [20251071] Spam Checks started.
11:35:45.141 [20251071] Spam Checks skipped: User authenticated
11:35:45.141 [20251071] Spam Checks completed.
11:35:45.141 [20251071] Removed from SpamCheckQueue (0 queued or processing)
11:35:48.098 [20251071] Added to LocalDeliveryQueue (1 queued; 0/50 processing)
11:35:48.098 [20251071] [LocalDeliveryQueue] Begin Processing (priority Normal).
11:35:48.103 [20251071] Starting local delivery to alias-target@mydomain.com
11:35:48.104 [20251071] Message saved to MailProcessing directory for alias-target@mydomain.com. File name: 20251071-20008-NOID.tmpmsg
11:35:48.104 [20251071] Delivery for me@otherdomain.com to alias-target@mydomain.com has completed (Delivered) Filter: None
11:35:48.104 [20251071] End delivery to alias-target@mydomain.com (MessageID: <e472600400394de7b6c68c522a3dea15@23c9dbc51190498f811c6a5a56cd4632>)
11:35:48.108 [20251071] Removed from LocalDeliveryQueue (0 queued or processing)
11:35:51.097 [20251071] Removing Spool message: Killed: False, Failed: False, Finished: True
11:35:51.097 [20251071] Failed to generate bounce message for empty alias.
11:35:51.097 [20251071] Delivery finished for me@otherdomain.com at 11:35:51 AM    [id:20251071]