Currently, in simple single discussion forum if user changes name and/or introduction of forum, then existing discussion subject and/or message gets updated with forum name and/or introduction.
Please check if this is a valid case, as we have separate setting for changing forum and discussion, hence they should not implicitly change each other.
Steps to reproduce:

1. Log in as an admin
2. Enter a course and create a new single forum with the name and description `Test 1`.
3. Save and display. Note the title and description of the discussion.
4. Edit the forum and change the name and description to `Test 2`.
5. Save and display. Note the title and description of the discussion has been changed as well.

Problem:

1. Create a new standard forum for general use forum
2. Add two discussions
3. Change forum type from standard forum for general use to simple single discussion forum
4. Check discussion subject and message is replaced with forum name and introduction.
5. Change forum type to standard forum for general use and it retains forum name and introduction for that discussion.