Unfortunately, we are simply unable to reproduce this problem. The EC buttons are showing up on our test sites as expected. We do see multiple reports of this, though, so we agree something must be wrong, but it’s proving very difficult to troubleshoot since we cannot reproduce it.
If anybody could allow us direct access to their site so we can troubleshoot there it would be helpful. If you can do this please submit a ticket here and provide temporary login credentials for your site.