Using email address as username and bulk upload Role issues as a result

Hi All

I wonder if someone could clarify an issue we have.

Let me set the stage:

We have a limited amount of Contractors (31) that have an email address as their username in Fusion.

every month, we perform a clone of our production system to a DEV environment and need to upload the previous roles that these limited contractors had before the clone.

(Initially, all of our staff use a number prefix as a username, it is only the limited contractors that we are having this issue with)

when performing the upload through Data Exchange we get the following errors when we use these particular contractors that have email addresses: