I'm editing release 060d5875-5b8d-4d56-8975-bcc19478e866 on the beta server (b3d55ec):
http://beta.musicbrainz.org/release/060d5875-5b8d-4d56-8975-bcc19478e866/edit
Track 19 is titled "Tryin' to Get to You".

If I press the "Guess Case" button at the bottom, the first "to" turns to "To" resulting in "Tryin' To Get to You".
If I press the "Guess Case" icon (looks like "Aa") at the right of the track title, the "To" correctly turns to "to" again, resulting in "Tryin' to Get to You".

The "Guess Case" icon works correctly, the "Guess Case" button seems to have problems with the Unicode apostrophe (U+2019).