After updating our site to J4, when someone receives a comment on their user profile, an email is no longer sent to them notifying them that they received a comment.
We use an Autoaction to send an email to the person who received a comment and we BCC our admin email. Admin still receives the email, but the To: line in the email admin receives shows To: undisclosed-recipients: ; and the user that received a comment does not receive the email notifying them that they received a comment. It worked as needed prior to upgrading. For reference, we use Comments as a way for users to leave feedback on another user's profile. We use a profile tab called "Feedback". The tab is linked to a field of type Comments. We have similar email Autoactions for things like Notification of Connection Request, Notification of Connection Accepted, etc. and they all work as they did before.

Settings for the problematic Autoaction (there are no Conditions set):

 

To: address is left blank as per tool tip recommendations - Leave blank to use trigger user for the to email address. It worked prior to upgrade...
 

 

Joomla! 4.4.3
Community Builder 2.9.1
PHP Version 8.2.15
Database Type mysql
Database Version 8.0.35-percona-sure1

Those settings resolve the "To: undisclosed-recipients: ;" issue, but the comment notification email is sent to the person who made the comment, not to the user who is receiving the comment

After changing to Specific User: [var2_user_id] and Triggers: activity_onAfterCommentStreamCreate, the email notification goes back to  "To: undisclosed-recipients: ;" and the user who received the comment does not receive an email notification.