"Sorting on fields that need arguments to resolve is deprecated" warning (w/ example repo)

Following up on https://github.com/gatsbyjs/gatsby/issues/28565 I created a repo with a sample where this warning occurs:

https://github.com/rejas/deprecate_repo

Description

When building my site I get this warning:

warn The enum value "MdxFieldsEnum.fields___slug" is deprecated. Sorting on fields that need arguments to resolve is deprecated.

Steps to reproduce

Build the example repo https://github.com/rejas/deprecate_repo

Expected result

No warnings should appear

Actual result

Warnings appear

Environment

System: OS: Linux 5.4 Ubuntu 20.04.2 LTS (Focal Fossa) CPU: (8) x64 Intel® Core™ i7-8565U CPU @ 1.80GHz Shell: 5.0.17 - /bin/bash Binaries: Node: 16.1.0 - ~/.nvm/versions/node/v16.1.0/bin/node Yarn: 1.22.5 - /snap/bin/yarn npm: 7.11.2 - ~/.nvm/versions/node/v16.1.0/bin/npm Browsers: Chrome: 90.0.4430.212 Firefox: 88.0.1 npmPackages: gatsby: ^3.5.1 => 3.5.1 gatsby-background-image: ^1.5.3 => 1.5.3 gatsby-plugin-feed: ^3.5.0 => 3.5.0 gatsby-plugin-image: ^1.5.0 => 1.5.0 gatsby-plugin-manifest: ^3.5.0 => 3.5.0 gatsby-plugin-mdx: ^2.5.1 => 2.5.1 gatsby-plugin-no-sourcemaps: ^3.5.0 => 3.5.0 gatsby-plugin-offline: ^4.5.1 => 4.5.1 gatsby-plugin-react-helmet: ^4.5.0 => 4.5.0 gatsby-plugin-robots-txt: ^1.6.2 => 1.6.2 gatsby-plugin-sharp: ^3.5.0 => 3.5.0 gatsby-plugin-sitemap: ^4.1.0 => 4.1.0 gatsby-remark-copy-linked-files: ^4.2.1 => 4.2.1 gatsby-remark-images: ^5.2.1 => 5.2.1 gatsby-source-filesystem: ^3.5.0 => 3.5.0 gatsby-theme-material-ui: ^2.0.1 => 2.0.1 gatsby-transformer-sharp: ^3.5.0 => 3.5.0 gatsby-transformer-yaml: ^3.5.0 => 3.5.0

[phun-ky]

Issue still persists, need documentation on how to use slug for sorting (or equivalent)

[mbcod3]

graphql shows warning if you use field to sort that was created using gatsby api creatNodeField