Cant load browser cached content

Hello,

if im load a “porfolio gallery” first time in browser(firefox & edge), everything works fine. But if i reload the page, after the portolio gallery is in browser cache, the most time i cannt see annything.

I already has updatet wordpress, plugins and the theme.
Restoring a backup doesn’t help either.

You can try it. Just click on the link https://diebauplanfabrik.de/aktuelle/ after the gallery has load, just click in the menue on “Atkuelle Projekte” and see what happes. Sometimes the Portfolio Gallery will load, try it 3-4 times.

Has someone any ideas or can tell me how i can search for a solution?

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