[plugin: dFactory Responsive Lightbox] Not injecting lightbox code

I have used lightbox plugins like Foobox in the past, but the lightbox functionality stopped working on new posts a few months ago. I have switched to the dFactory plugin, switched themes and uninstalled plugins but the relevant lightbox code doesn’t seem to be injected into any new posts, even though the script loads in the header.

Here is an old post where lightbox code works on post images: https://sjp.id.au/photography/lensbaby-velvet-56-lens/

Here is a new post where the lightbox functionality does not work at all: https://sjp.id.au/photography/murray-river-photos/

No lightbox plugins seem to be working now.