This topic closed before I saw it.
https://kriesi.at/support/topic/fullwidth-masonry-gallery-image-loading-issue/
I just wanted to second that this is infact an issue if the masonry gallery is trying to load a large number of photos. What I have noticed is upon loading the page if the viewer does nothing and the gallery finishes loading and then you scroll down the page everything is fine. But if you start scrolling down the page while images are still loading then all hell breaks loose so to speak. I can second above that if you refresh or resize the browser window after it is finished then it will fix itself.
So you can close this, but I wanted to second that there is infact a bug going on here. I have seen it is chrome and safari
Hey allegrabillings!
As was noted at the end of the topic it looks like a bug and a temporary fix was provided.
Best regards,
Devin