Images not displaying in articles for users who are not signed-in (but display fine for those who are)

For some reason, there are some articles in our knowledge base that do not display for users if they're not signed in. Other images in the same article display fine; it's somehow only an issue for some images. One example is this public article: https://careportal.zendesk.com/hc/en-us/articles/360058117733

Screenshot of what the image looks like if you're not signed in:

And then if you're signed in: