Links added to Blog Post images not saved

I’ve learned from HotJar that users often click on images in my blog posts, so I want to create relevant links. I’ve gone into the Rich Text Field that contains the images and:

  1. clicked on the image to show the configuration menu
  2. clicked on the “wrench” icon
  3. clicked on the Link option
  4. selected “External URL”
  5. pasted the appropriate URL into the field.
  6. clicked “Save” the post

When I re-open the post and repeat steps 1-3, the Link option has reverted to “Link to: none.”

What am I doing wrong?

Here is my public share link: How to find your next dress shirt in 5 minutes, without ever setting foot in a store