OK i see what you mean now.
This means the conflict is not originating from the FVM plugin. This means that it could be another plugin or your theme causing the conflict.
Looking at your page source the data-foogallery attribute is:
data-foogallery="{"item":{"showCaptionTitle":true,"showCaptionDescription":true,"maxCaptionLength":0,"maxDescriptionLength":50},"lazy":false,"src":"data-src-fg","srcset":"data-srcset-fg","paging":{"type":"dots","theme":"fg-light","size":6,"position":"both","scrollToTop":true},"template":{"gutter":30,"columnWidth":330,"align":"center"}}"
If you look at the page source on a demo of ours (https://foo.gallery/demos/pagination-demo/), you see this:
data-foogallery="{"item":{"showCaptionTitle":true,"showCaptionDescription":true},"lazy":true,"src":"data-src-fg","srcset":"data-srcset-fg","paging":{"type":"dots","theme":"fg-light","size":3,"position":"bottom","scrollToTop":false}}"
You can see that in our demo, the data is correctly encoded, but from your site it is not. This suggest that another plugin or your theme is conflicting with the way attributes encoding works.