PD4ML Probe currently embeds v380fx5 – probably that is the reason. (I assume in PD4ML Probe you check generated PDF, not a web browser preview)

I’ve just tested your HTML with fx5 – images #3 and #8 are missing in the resulting PDF.

It seems image #3 URL returns a redirect, which is not supported.

If I open the HTML with a web browser – only image #8 is missing. However if I copy-paste image #8 URL to the address bar of the web browser – it shows it. I’ll let you know our analyze results.