Problem with Subscribers automatically set in "Author" joomla group

Hello,

Every time a user becomes an active member or subscriber in Membership Pro, they become part of the "Author" joomla group automatically. Which is not supposed to be the case.

I checked the joomla group settings in Subscription Plans: "Author" is not ticked anywhere.
Where does this problem come from would you say?

It's from Joomla! configuration. Go to Users -> Manager, click on Options button in the toolbar, set New User Registration Group parameter to Registered (I believe right now, it's set to Author), then check it again, it should work as expected

See this screenshot to see the setting I am talking about drive.google.com/file/d/14lw85kxXwEDVbTS...DO/view?usp=drivesdk

Regards,

Tuan

Thanks, I checked but the New User Registration Groupe Paramater is already set to "Registered".
Where else could it come from would you say?

(apparently, it doesn't happen when Membership Pro subscribers are uploaded manually)