Please, consider the topic closed. Not necessary any more.
The support responce time is terrible, by the way.
The problem is reproduced when Image Link functionality is setup to Lightbox Linking Deactivated (custom links will still be used).
It works fine in Lightbox Linking Active Mode.
The problem is related to the specific page, not setup.
I created a new page with advanced builder using only masonry gallery, and it displays fine.
I have the same problem. Masonry not showing in frontend.