Project page/Gallery grid loading super slow or not appearing until scrolling down far.

Site URL: https://badger-chrysalis-w8ph.squarespace.com

Hello! 

I am having trouble with my site when it comes to the "Our Work" page. I included a "Portfolio" section into this page and I can not figure out why, when first clicking on the page, that the portfolio section takes so long to appear and sometimes does not even appear until you are halfway down the page. Any ideas why there is such a lag on it loading and do you have any recommendations? It is especially bad on the phone layout as you will see from the example video I have attached below. 

Anything helps thank you! Video example attached below. 

I think I found a fix for this by doing some research where I found the same issue on another forum. Allot of the folk said to add this code which ended up solving the issue (for now):

div#gridThumbs {
    opacity: 1 !important;
    transform: unset !important;
}
.portfolio-grid-basic .grid-item .portfolio-title {
    opacity: 1 !important;
    transition: unset !important;
}