SSL Subscribing/Unsubscribing Issue

How to reproduce:
When using SSL and clicking the subscribe button on a user's page, an ajax request is made, subscribes you and returns an xml response. This response cannot be parsed and returns a parse error. The subscribe button becomes empty.

The user is still subscribed, the only error is when the ajax call returns.

I am using the latest version, installed yesterday to make sure it was not an old version problem.

Possible reason:
I have found that when using SSL, there is an "l" character in the beginning of the page returned before the doctype for every apge. It does not break the html, but when it returns XML, it's not valid anymore. This could be the reason for the parse error.