When marking a message as read in a shared mailbox, no events are triggered by Cyrus. As opposed to marking a message read in a personal folder where a "MessageRead" is sent out.
Here's the IMAP log from the operation in question where no events got recorded in the log:
```
C: A0005 SELECT "Shared Folders/shared/Collected"
S: * 2 EXISTS
S: * 0 RECENT
S: * FLAGS (\Answered \Flagged \Draft \Deleted \Seen)
S: * OK [PERMANENTFLAGS (\Answered \Flagged \Draft \Deleted \Seen \*)] Ok
S: * OK [UNSEEN 2] Ok
S: * OK [UIDVALIDITY 1429518712] Ok
S: * OK [UIDNEXT 3] Ok
S: * OK [HIGHESTMODSEQ 16] Ok
S: * OK [URLMECH INTERNAL] Ok
S: * OK [ANNOTATIONS 65536] Ok
S: A0005 OK [READ-WRITE] Completed
C: A0006 UID STORE 2 +FLAGS.SILENT (\Seen)
S: A0006 OK Completed
```