When I first started watching the German 'Navajo Joe' Blu-ray - with the English soundtrack - I noticed the discrepancy with the music in the opening titles straight away. To say that I was peed off would be an understatement, because I love the full version of the opening title....which you do not get with the English track!
Because there is literally no dialogue leading up to the opening title music, I now - when viewing the blu-ray - watch the film with either the German or Italian soundtrack - up until the end of the credits, and then quickly flick my remote control hand-set back to the English language. This means I can get the full benefit of the opening title music, and then enjoy the rest of the film in English.
I don't know who buggered up the full Ennio Morricone title track for the English audio.....but they need their cigarillos removing!!