The fooBarHtml node is always null

[matthewgoslett]

I'm using a fresh install of:
"gatsby": "^3.4.1"
"gatsby-plugin-json-remark": "^1.1.5"

Given a sample data file skill_sets.json:

[
  {
    "title": "PHP",
    "content": "Hello World **test**",
    "images": [
      "../images/skills/languages/php.svg"
    ]
  }
]

The markdown in the content field is parsed correctly and I can access it via the jsonRemark node; however the contentHtml node added to the tree here is always null.

{
  "data": {
    "allSkillSetsJson": {
      "nodes": [
        {
          "id": "7ab6f92d-807f-521d-94f3-a78f59ef2634",
          "title": "PHP",
          "content": "Hello World# **test**",
          "contentHtml": null,
          "titleHtml": null
        }
      ]
    },
    "skillSetsJson": {
      "contentHtml": null,
      "content": "Hello World# **test**",
      "id": "7ab6f92d-807f-521d-94f3-a78f59ef2634"
    },
    "jsonRemark": {
      "id": "75929503-59e5-57e0-8cfb-a14c8aa17cd5",
      "children": [],
      "_0": {
        "contentMarkdownRemark": {
          "id": "3d290d74-f977-530e-b221-c16a3e6909cd",
          "html": "<p>Hello World# <strong>test</strong></p>"
        }
      }
    }
  },
  "extensions": {}
}