GitHub import did not properly match all accounts with same e-mail address

After importing a repository from GitHub, some accounts were not properly matched with the ones from gitlab. I have tried it multiple times with different settings (see migration notes below).

URLs:

• https://github.com/postmarketOS/pmbootstrap
• https://gitlab.com/postmarketOS/pmbootstrap

Relevant notes (from here):

I've compared my accounts to @craftyguy's accounts. The import has always worked for @craftyguy, while it did not work three times for my account. We suspect that caching is the issue.

Comparing accounts

@craftyguy:

• registered with same e-mail and username in both gitlab and GitHub
• e-mail set to hidden in gitlab
• e-mail set to hidden in GitHub
• "Social sign-in" enabled on gitlab for GitHub

@ollieparanoid (first try):

• registered with same e-mail and username in both gitlab and GitHub
• e-mail set to hidden in gitlab
• e-mail set to hidden in GitHub
• "Social sign-in" not enabled on gitlab for GitHub

@ollieparanoid (second try):

• registered with same e-mail and username in both gitlab and GitHub
• e-mail set to hidden in gitlab
• e-mail set to show in GitHub
• "Social sign-in" not enabled on gitlab for GitHub

@ollieparanoid (third try):

• registered with same e-mail and username in both gitlab and GitHub
• e-mail set to hidden in gitlab
• e-mail set to show in GitHub
• "Social sign-in" enabled on gitlab for GitHub