Create user REST API endpoint is creating users inconsistently

Issue Summary

When using the POST /rest/api/3/user, the created users are in an inconsistent state. 

Steps to Reproduce

Create a user via POST /rest/api/3/users

curl --request POST https://site.atlassian.net/rest/api/3/user \
--user radmin_email:apitoken \
--header 'Accept: application/json' \
--header 'Content-Type: application/json' \
--data '{"emailAddress": "user@newuser.com","displayName":"New User"}'

Expected Results

The user should be created with the application access configured for the new user in the Product access configuration

Actual Results

Possible results

• User is created without site access
• User is added to an application access group that is not configured for new user.

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available