Using remote gallery images in Tab

Tabs responsive generally works well in a tabbed page including with gallery shortcode from Responsive Lightbox & Gallery.
That is it is OK when the gallery images are from wordpress media.

However if I use a remote library of images (in my case Flickr for the gallery images) there are various problems.

At first the tab gallery page saves and looks fine, but when I return again to the edit page it is completely jumbled (that is the edit page is jumbled up) and on attempting to save the page with tabs once again I get the message…
Updating failed. Error message: The response is not a valid JSON response.

I realise it’s possibly a fairly unique combination of circumstances, could be multiple causes and probably not easily resolved, but just thought I’d mention it.

Many thanks.