This is a slightly contrived example of an issue in Gatsby that occurs in the niche situation of importing an external file into gatsby-config as a plugin's pluginOptions- when that imported file changes but gatsby-config does not, the resulting build does not have its cache cleared and can cause changes that would result from the configuration change not to occur in the resulting build.

1. gatsby develop

2. Navigate to localhost:8000/example-post

3. Uncomment the commented line in mdx-options.js

4. Relaunch gatsby develop and refresh localhost:8000/example-post

5. Notice that the page does not use post-template.js (shown with padding and a black border)

6. Close gatsby develop and run gatsby clean before relaunching

7. Refresh the browser again, and notice that the page changes once the stale cache is cleared