Thanks for looking into this.
Steps to reproduce:
Step 1: in the toolbar click on Forums, then Add New.
You should see something like this: https://imgur.com/a/o6VZZ6F
(The Forum Attributes menu that’s in the top left is from bbPress and the Forum Attributes in the bottom left is from Redux.)
Step 2: Add a title to the new forum and then publish.
Step 3: Add New forum, give it a title, set visibility to private, and then publish.
Step 4: Add New forum, give it a title, click on parent inside bbPress’s Forum Attributes, you should see both forums you’ve made so far, click the one you’ve made private, and then publish.
The forum is published but the parent is reset to — No parent —
Step 5: Click on Redux’s Forum Attributes, you can’t see the private forum and thus can’t select it.
This bug also applies when Type is set to Category and when Visibility is set to Hidden.
A partial workaround is to temporarily disable Redux, which allows one to set a parent of a Private/Hidden Forum/Category but once Redux is enabled again if the forum is ever edited the parent is reset to — No parent —.
