The topic content disappeared after updating to WordPress 6.8

[arl1nd]

After updating to WordPress 6.8, the topic content in bbPress forums no longer displays on the front-end. The issue occurs immediately upon upgrading, even with the Twenty Twenty theme and bbPress as the only active plugin. No custom code or other plugins are involved.

Steps to reproduce:

1. Install WordPress 6.8.
2. Activate the Twenty Twenty theme.
3. Install and activate bbPress.
4. Create a new topic in a forum.
5. View the topic on the front-end and see the topic content is missing, only the title appears.

Workaround:
Reverting to WordPress 6.7 restores the topic content display, confirming a regression introduced in version 6.8.

[arl1nd]

Duplicate of #3631.