It is a Dropdown field with ~150 Options (I have no idea if this could somehow affect the outcome. But it sounds unlikely)
I am using the BuddyPress Registration form, styled by the Youzify plugin.
I am not using any Cache Plugins.
Can grant you admin access if you want.
Thanks for the prompt reply. I really need this plugin to work!
To answer your questions:
1. Are you single or multiple conditions for joining the group?.
2. What are the field types you are comparing with what operators?.
Xprofile Field –> EQUAL TO –>
3. What registration form you are using is BuddyPress or any other?
I am using the Youzify form. Which -I think- is basically the BuddyPress form but with make up.
I tried deactivating Youzify and then created a new user. Still got the same result.
New user was not added to the group automatically.
HOWEVER, when manually syncing that group from the Auto List settings, the user was synced and added to the group.