Using SCIM to add a user two separate Groups on gitlab.com fails

Summary

Want to use SAML/SCIM to create/map users in 2 distinct top-level groups (on gitlab.com), where some users need to be members of both groups.

For the first group (at which point the user have not been created), once the sync runs, the user get created in GitLab.com and is added to the first group.

For the second group, by which point the user already exists on GitLab.com -> It errors out after the sync, and the user does NOT get added to the group.

What is the expected correct behavior?

User should be added to the (second) group

Output of checks

This bug happens on GitLab.com

Possible fixes

Identified by @jamedjo : "it looks like SCIM create always uses Users::BuildService and tries to create a new user, which would likely fail with an email conflict"