No email notifications on mentions in comments

[lutalex]

Steps to reproduce:

1. As user_1 create an ONLYOFFICE Document (Document.docx) via NextCloud portal.
2. As user_1 share the document with user_2.
3. As user_1 add some text to the document and then add a comment to some block of this text. Mention user_2 in this comment.

Expected results:

1. user_2 is notified by email about being mentioned in Document.docx.

Actual result:

1. user_2 gets no email notification about being mentioned in Document.docx.

Environment:

1. On-prem deployment of NextCloud v22.1.1
   • with ONLYOFFICE-Nextcloud connector v7.1.2.
2. On-prem deployment of ONLYOFFICE Docs Community Edition v6.4.0.

Additional comments:

2. If a document is being shared with user_2 via mentioning, i.e. user_2 had no access to the document prior to being mentioned, then she will get notified by email about receiving a share.
3. Similar behaviour is observed within ONLYOFFICE Spreadsheet.

[samuk]

I also have this issue.