What is the order of priority of image previews for discourse links on twitter?

So, I am struggling with this. I have two posts that behave differently and I can’t figure out why. One post shows the onebox preview image in twitter. The other shows the twitter_summary_large _image.

This post works as expected.
https://community.abs-consulting.com/t/welcome-to-issue-65-of-the-abs-devops-scm-e-newsletter/22

This post does not work as expected.
https://community.abs-consulting.com/t/devsecops-platforms-help-smbs-scale-as-they-grow/113