Please check the below mentioned points to get root cause of the issue.
Check whether user have disabled the notification option by using communication preference.
Check whether in respective pulse action related notification channel rule the notification option was disabled.
Check whether in pyProcessNotification queue processor you are getting any exceptions when some update is getting happened during pulse interaction, this queue processor will be responsible for triggering all pulse related actions.
Yes notification preference is set to receive the messages and notifications instantly. Also, respective queue processor is working fine and no broken processes identified.
Also, there is one critical observation i would like to share and request analysis on. i.e., when I post some message from a different user (say User2) who is having same access group as User1 , I am able to receive notifications instantly.
But when User 3 of different access group is trying to refer User1 in some Pulse chat under any case, they are not available for User1.
Kindly, Please share analysis on this aspect which would help me a great deal! Thanks in advance!
Your notification rule is in Org level ruleset (or) in application-level ruleset?
If you want to tag other application user's also then your notification rule should be in Org ruleset.
What should be the issue is for the second application user in Index-Notification-Preference you will not be having needed details.
Index-Notification-Preference - This is the table where Pega will maintain the user notification preference related information. In in-case in this table needed information is not avail then system will not send any mail to users.