It's because of the highly inefficient way that you are loading that content.
Yes, it's true; it's an immediate and simple solution. Because I didn't think it could generate such a problem.
This is really not the way that you should be doing this. That module should be assigned to a module position on the layout of your outline (not embedded in an article).
It was a choice of fast insertion (from this image grid) and for graphics reasons; to allow the gallery to always be in any resolution immediately below the article. Otherwise, as I have done in other parts in this same wesite, insertion is more laborious. Furthermore, subdividing the modules into different positions often creates white spaces in the different resolutions.
Following the more correct approach as you indicated, I created a new special menu (advertisers), in order to create the association with the image grid module. The position (in the layout) below the main content is already provided (Main-bottom) where I have now placed this form.
As always, you're right. Now, even without the atom, the gallery does not lose the settings and the lightcase is also executed with the joomla cache.