Hi,
I'm having a similar issue! I have a test website so I don't damage the live site and when I added a headline to the homepage the transparent header stopped working. It works well across all other pages, so I assume it has to be a problem with the multi-image headline?
Also, I tried moving other elements above the headline and the transparency works again. This makes me think even more that the problem has to be the headline.
Any advice to solve this?
Thanks!!!