Let users edit the subject has different effects depending on the user rights

[rich20]

Describe the bug
https://www.kunena.org/forum/general-questions-and-how-tos/156603-can-change-the-topic-title-when-replying
https://www.kunena.org/forum/36-German/157686-wenn-nutzer-thema-beim-antworten-wechselt
This bug is related with this bug #6177

To Reproduce
Steps to reproduce the behavior:

1. Set in the configuration tab Frontend "Let users edit the subject = Yes" (is default)
2. Login as Admin or global Mod and click on Reply and change the subject
3. Login as normal Registered User, click on Reply and change the subject

Expected behavior
The title should be changed only at the answer message

Actual result

• Logged in as Admin - The topic title will be changed for the complete topic
• Logged in as global Mod - The topic title will be changed for the complete topic
• Logged in as normal User - Nothing will be changed, but when a mod or admin answers this message, the complete topic get the attempted change of this user.
• Logged in as normal User - The complete topic title wiil be changed when he is the author of this topic

System information (please complete the following information)
Joomla version: 3.9.4
Kunena version: 5.1.11-DEV
Php version: 7.3.2

Please see my updated reply too

[github-actions]

This issue is stale because it has been open 30 days with no activity.

[rich20]

Update:
https://www.kunena.org/forum/k5-1-support/159315-are-you-ever-going-to-fix-the-bug-which-changes-topic-titles

To Reproduce

1. Set in the configuration tab Frontend "Let users edit the subject = Yes" (is default)
2. Login as normal Registered User, click on Reply and change the subject

Expected behavior
The title should be changed only at the answer message

Actual result

• The complete topic title wiil be changed when he is the author of this topic

[rich20]

At the messages are the changes now correct and remain as it should. But one of this problem still exists.

• When a mod, admin or the topic author changes the title for a message, it changes also the topic title.