[Julia]

@mike80222:
I have no answer. I wish someone resolve it.

[Julia]

1. Which version of WordPress are you running?
⇒WordPress 5.6.1

2. Did you install WordPress as a directory or subdomain install?
⇒As a directory

3. If a directory install, is it in root or in a subdirectory?
⇒subdirectory? full pass /home/users/1/〇〇〇〇〇〇/web　

4. Did you upgrade from a previous version of WordPress? If so, from which version?
⇒Yes. WordPress　5.5.3　
But it is the first try to see wrong display in buddypress.
I am beginner.

5. Was WordPress functioning properly before installing/upgrading BuddyPress (BP)? e.g. permalinks, creating a new post, commenting.
⇒Yes properly.

6. Which version of BP are you running?
⇒Version 7.1.0

7. Did you upgraded from a previous version of BP? If so, from which version?
⇒Probably　No.

8. Do you have any plugins other than BuddyPress installed and activated? If so, which ones?
⇒bbpress Version　2.6.6
Other plugins are unactive in the test.

9. Are you using a standard WordPress theme or customized theme?
⇒a standard WordPress theme

10. Which theme do you use ?
⇒Generatepress Version 3.0.2

11. Have you modified the core files in any way?
⇒No

12. Do you have any custom functions in bp-custom.php?
⇒No

13. If running bbPress, which version? Or did your BuddyPress install come with a copy of bbPress built-in?
⇒bbpress Version　2.6.6
copy ⇒Unknown

14. Please provide a list of any errors in your server’s log files. https://codex.wordpress.org/Debugging_in_WordPress

⇒The code is adding.

 // WP_DEBUG debug mode
define( 'WP_DEBUG', true );

// /wp-content/debug.log 
define( 'WP_DEBUG_LOG', true );

⇒No error message!
⇒No log file generated. In short,　no bug?

15. Which company provides your hosting?
⇒lolipop.jp[Japan]

16. Is your server running Windows, or if Linux; Apache, nginx or something else?
⇒Linux（CentOS）
⇒　Apache

17. Which BP Theme are you using?
⇒Buddypress Nouveau

18. Have you overloaded any BuddyPress template files.
⇒Unknow

19. Any other site customisations that might have a bearing on the issue?
⇒No. 　After remove customisations code in bbpress, I checked it.

20. What BP Template Pack is activated in your installation? You will see that under Dashboard > Settings > BuddyPress – Options page.
⇒Buddypress Nouveau

Basic Trouble Shooting:

1. Identifying whether you have a theme issue:
⇒I tried other two themes[ Onepress and Twenty Twenty-One],
but the icon[×] trouble occurred in buddypress profile page.(Nothing happens)

2. Plugins:
⇒In the bbpress is activated only, the icon[×] works completely.(The topic deleted!!)
In the bbpress and buddypress set, the icon[×] trouble occurred in buddypress profile page.(Nothing happens)
Both test, the other plugins are invalid(not active).

3. BP Themes:
Both Buddypress Nouveau and Legacy, same wrong display.(Nothing happens)

I think it is something wrong with the icon[×] button? on forum section in buddypress.
Nothing happens when that [x] is clicked.

[Julia]

There is also an icon [x] implying that I can unsubscribe/unfavorite that item.
However, nothing happens when that [x] is clicked. (your comment)

I have same problem, too. Buddypress(7.1.0)+bbpress (2.6.6) installed.
It seems that buddypress do not support bbpress favorite.
Adding the favorite topic works, but Removing the favorite topic does not work.
After [x] is clicked, buddypress is invalidated thereafter.
I could check the [x] topic removed. In short it is the display bug in the buddypress.

I have no answer to resolve display bug in buddypress.