Images in mdx frontmatter not registering as images

[m-salmankhan]

When I query an image that's in mdx frontmatter, it returns a string (exactly as it appears in the markdown) instead of the GatsbyImage object.

---
title: Title Here
description: >-
  This is the description for this post
thumbnail: image.jpeg
---
# Body content here
![](image.jpeg)

Query:

query MyQuery {
  allMdx(filter: {fields: {post_type: {eq: "example"}}}, limit: 6) {
    edges {
      node {
        fields {
          slug
        }
        frontmatter {
          thumbnail
          title
        }
      }
    }
  }
}

The thumbnail returned by the query is "image.jpeg".

However, the image in the body is automatically turned into a GatsbyImage, so the image path is definitely correct.

The images are in the same directory as the mdx file.

My gatsby-config has:

        "gatsby-plugin-sharp",
        "gatsby-transformer-sharp",
        "gatsby-plugin-image",
        {
            resolve: `gatsby-plugin-mdx`,
            options: {
                gatsbyRemarkPlugins: [
                    {
                        resolve: `gatsby-remark-images`,
                        options: {
                            maxWidth: 1500,
                        },
                    },
                ],
            },
        },

[m-salmankhan]

Abort mission; running gatsby clean for the third time in a row somehow magically fixed it .-.