User Management REST API is not working on some Organizations

Issue Summary

The User Management REST API is not working on some Orgs. 

Steps to Reproduce

1. Generate an admin API key following these steps, on an Org you are an admin.
2. Try to call any of the endpoints listed in the User Management REST API.

Expected Results

The user should be able to use the API as expected.

Actual Results

The API returns below error:

{"key":"forbidden.insufficientScope","context":{"message":"Insufficient scope for this action","acceptableScopes":
["manage:org","manage:me:DUMMYSCOPE"]},
"errorKey":"forbidden.insufficient-scope","errorDetail":{"message":"Insufficient scope for this action","acceptableScopes"
["manage:org","manage:me:DUMMYSCOPE"]}} 

Workaround

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