Can you try enabling safe-mode to see if the issue persists?
I am currently unable to reproduce the error which you are seeing which suggests to me that it may be related to a theme or a plugin that you have installed.
Do you know how you managed to have “everyone” with full permissions and additional groups in the configuration?
For me, saving something like that doesn’t work:
I wonder whether saving additional groups in combination with “everyone” having all permissions was possible in the past and is causing trouble now.
There have also been recent cases where saving permissions failed due to another setting. The colour in the general tab did not meet the new requirements[1] and that prevented saving because the whole configuration is saved at the same time. So it might be worth checking what you have configured in the other sections and whether there are any similarities between the forums.
That seems like an oversight.
If I have a subcategory that needs to have it’s permissions updated but has more restrictive rights, I can’t when the parent category has everyone permissions.
Can you share an example configuration that is a problem?
You can have a parent category which everyone is able to see, and group A is able to see and post and a subcategory that only group B is able to see and reply. Therefore you don’t need to add group B to the parent category
Like this (“jeder” is the German term for everyone)