Steps to reproduce the issue

• Install Usergroup Selector (http://function90.com/products/usergroup-selector.html)
• Enable Usergroup Selector and select some groups at the "Allowed User Groups" field.
• Enable Joomla User - Profiles and require TOS and select TOS article
• Register a user from frontend with a group

Expected result

User will be created with the selected group/groups.

Actual result

User created, but without groups. This is because the JUser->save() is returning false. While further investigating the problem. its telling me the error using the following:
$juser->getError();
This is the result i got: Please read the Terms of Service. You will not be able to register if you do not agree with them.

(these snippets are found in the onUserAfterSave function within the plugin)

My guess is that there is a issue with the User-Profile plugin from joomla. since everything is going fine when i haven't got a TOS Article selected.

System information (as much as possible)

Problem accours on the the following platforms:

• Windows 10 running latest version of Xampp
• MacOS running latest version of Mamp pro
• Ubuntu running webmin with apache2 server

All the instances are running a clean setup of joomla 3.8.1

Additional comments

Teamviewer is possible if needed, also remote joomla login is do-able.