'Unknown aspect ratio' warning and no image preview for some card images

[Eliasvdb]

Description of issue:
For some of our URL’s, the card validator does not show the image, when inspecting the network call that is done we can see a warning:

twitter:image:id: "Unknown aspect ratio"

Both the images that work and the ones that don’t are from the same domain, our image store.

URL affected:
https://www.vrt.be/vrtnu/podcasts/radio1/t/touche/6/kris-merckx/
Results in:

Other similar URL that is working as expected:
https://www.vrt.be/vrtnu/podcasts/radio-2/d/de-spiegel/1/alex-agnew---ik-heb-goei-benen-in-een-rok-/
Results in:

Troubleshooting steps attempted:

• all meta tags are present (we use prerender.io for prerendering of SPA pages)
• Twitterbot is allowed to approach our URL’s
• we use full image URL’s from a completely publicly accessible domain
• we had a similar problem a week ago, 2 images from the same domain, one can be loaded, the other one can't in Twitter cards using card validator, all images (both the ones working and the ones not working) are now stripped from all exif and icc data, but still the problem occurs occasionally

We do not see any other feedback than ‘unknown aspect ratio’ in the validator.