Missing e-mail to complete account creation when email has `+` (Gmail)

Summary

I wanted to register with a different username (to reflect my company's), but I'm not receiving mails, not even in spams.

Steps to reproduce

Try to sign-up. My email address has a + inside (since my bare e-mail address is already used by my other account). I do not know if it's safe (to spammers) to put a e-mail address here, but I could give it, it the same as my account's e-mail address with +gitlab before the @.

I tried multiple times to https://gitlab.com/users/confirmation/new but still no e-mail.

Example Project

N/A

What is the current bug behavior?

No e-mail received. Mails are using G-mail (business), and spam folder is empty.

What is the expected correct behavior?

E-mail received.

Relevant logs and/or screenshots

N/A

Output of checks

Happens on gitlab.com

Results of GitLab environment info

N/A

Results of GitLab application Check

N/A

Possible fixes

No idea.