To reproduce:

• Create a sandbox account using Special:MainPage. (The email address is mandatory in the form.)
• Receive a confirmation email sent to the provided address. Click the link to confirm the address.
• Make some stash translations.
• Log in as an administrator and promote the newly-created user.
• Go to the newly-created user's user page.

Observed:

1. The "Email user" link doesn't appear in the sidebar.
2. If you go to Special:EmailUser, this message appears:

"This user has not specified a valid email address"

Expected:

1. The "Email user" link must appear in the sidebar.
2. Special:EmailUser must allow sending an email.

The email is probably not stored correctly at some point in the sandboxed user creation process and both issues will probably fixed together.

Version: unspecified
Severity: normal