When adding Bitbucket as an external OAuth provider, this is how it looks like at the Phabricator login-page:
{F641980}
Instead of the Amazon-Logo, it should look like one of the Atlassian or Bitbucket - Logos:
{F641989}
PS: I'm running latest HEAD (c3e16e26c9fd7acdfa5c6a12d8c591ac46d7a857) from Sun Jul 19 07:43:20 2015 -0700.