As per https://phabricator.wikimedia.org/T124770#2014696
It seems that with https://gerrit.wikimedia.org/r/#/c/248312/ there are some cases in which when reloading the page when being in the middle of it won't load the images on the viewport.
Suspicions are that the document ready event is triggering before the browser moves the viewport to where it was before triggering the loadImages on the initial viewport instead of on the moved one.
Investigation needed.