I am in the process of migrating to a new developer account because I've changed my name.
I just tried to log into GitLab using my new developer account, but it failed with the following error: "422 Sign-in using Wikimedia Dev Account auth failed. Email has already been taken."
I assume this is because I previously signed into GitLab using my old developer account when it had the same email address attached (I've since changed it but that hasn't propagated due to T323880).
Old developer account
Wikitech username: Neil P. Quinn-WMF
Shell username: neilpquinn-wmf
New developer account
Wikitech username: Neil Shah-Quinn (WMF)
Shell username: nshahquinn-wmf