Not all tiles are shown on Ipad (Pro)

Hello. Installed version 4.2.2 of the Meow gallery plugin and version 3.1.5 of the Pro Lightbox version. I noticed that on our Ipads (Pro) not all tiles are shown on the page:
(Image 1). When I click on an “empty” images the complete image is shown in the Meow Lightbox Pro with all metadata
See images
After one or several refreshes of the page all images are shown. See image 2.

This only occurs on the Ipads. On Android systems SOME images are shown for 50%. On Window platforms it does NOT occur and all images are shown
.
Anyone an idea?
Henri

The page I need help with: [log in to see the link]