Mail grouping by thread - deletion of 1 message deletes others in other folders

[PatrykRzadzinski]

Steps to reproduce

1. Get a series of emails belonging to 1 thread
2. move them to a folder
3. Get another email and delete it
4. Email goes to trash but so the others from a folder

Same happens in case of

1. sending an email to a group
2. got mail delivery failure notification
3. delete the notification
4. original email gets deleted from Sent folder

Expected behavior

I would expect that actions such as move or delete ONLY apply to the emails grouped in given folder, such as INBOX. Moving a thread from inbox should not also move messages from Sent folder.

Actual behavior

Messages get moved, tbh I lost a lot of messages this way without noticing...

Mail app version

5.9.2

Nextcloud version

33.0.5

Mailserver or service

Exim

Operating system

Gentoo

PHP engine version

PHP 8.3

Nextcloud memory caching

No response

Web server

Nginx

Database

MariaDB

Additional info

No response