Masonry Alignment Problem

I’m experiencing a problem with the masonry layout (RPP V-5.2). These galleries were working fine until recently. I fixed the opacity 0/1 issue caused by WP 4.6 so possibly this is also related to the WP upgrade (or maybe it’s me!). You can see other examples under “Inspiration” in the top nav but here is one of the pages. (Custom theme):

https://www.ilightingled.com/inspiration/under-cabinet-indoor-lighting-gallery/

For this gallery I turned masonry off but it didn’t change anything:

https://www.ilightingled.com/inspiration/deck-stairlighting-gallery/

Hope you can help.