Duplicated mapping key error after 1 month hiatus

Hi, so when I go to publish my file I get this instead:

12:24:49 AM: Netlify Build
12:24:49 AM: ────────────────────────────────────────────────────────────────
12:24:49 AM: ​
12:24:49 AM: ❯ Version
12:24:49 AM: @netlify/build 29.56.1
12:24:49 AM: ​
12:24:49 AM: ❯ Flags
12:24:49 AM: accountId: 64c0e9e6de289942d7454aaa
12:24:49 AM: baseRelDir: true
12:24:49 AM: buildId: 67532511271fa400087bd491
12:24:49 AM: deployId: 67532511271fa400087bd493
12:24:49 AM: ​
12:24:49 AM: ❯ Current directory
12:24:49 AM: /opt/build/repo
12:24:49 AM: ​
12:24:49 AM: ❯ Config file
12:24:49 AM: No config file was defined: using default values.
12:24:49 AM: ​
12:24:49 AM: ❯ Context
12:24:49 AM: production
12:24:49 AM: ​
12:24:49 AM: ❯ Loading plugins
12:24:49 AM: - @netlify/plugin-lighthouse@6.0.1 from Netlify app
12:24:50 AM: ​
12:24:50 AM: Build command from Netlify app
12:24:50 AM: ────────────────────────────────────────────────────────────────
12:24:50 AM: ​
12:24:50 AM: $ npm run build
12:24:50 AM: > astro-paper@4.2.0 build
12:24:50 AM: > astro build && jampack ./dist
12:24:51 AM: 16:24:51 [vite] Re-optimizing dependencies because lockfile has changed
12:24:51 AM: 16:24:51 [content] Syncing content
12:24:51 AM: 16:24:51 [content] Content config changed
12:24:51 AM: 16:24:51 [content] Astro version changed
12:24:51 AM: 16:24:51 [content] Clearing content store
12:24:52 AM: duplicated mapping key
12:24:52 AM: Location:
12:24:52 AM: /opt/build/repo/src/content/blog/iron-lung_review.md:14:0
12:24:52 AM: Stack trace:
12:24:52 AM: at generateError (file:///opt/build/repo/node_modules/js-yaml/dist/js-yaml.mjs:1273:10)
12:24:52 AM: at storeMappingPair (file:///opt/build/repo/node_modules/js-yaml/dist/js-yaml.mjs:1448:7)
12:24:52 AM: at composeNode (file:///opt/build/repo/node_modules/js-yaml/dist/js-yaml.mjs:2531:12)
12:24:52 AM: at loadDocuments (file:///opt/build/repo/node_modules/js-yaml/dist/js-yaml.mjs:2778:5)
12:24:52 AM: at parseFrontmatter (file:///opt/build/repo/node_modules/@astrojs/markdown-remark/dist/frontmatter.js:19:23)
12:24:52 AM: ​
12:24:52 AM: “build.command” failed
12:24:52 AM: ────────────────────────────────────────────────────────────────
12:24:52 AM: ​
12:24:52 AM: Error message
12:24:52 AM: Command failed with exit code 1: npm run build (Search results for '"non-zero exit code: 1"' - Netlify Support Forums)
12:24:52 AM: ​
12:24:52 AM: Error location
12:24:52 AM: In Build command from Netlify app:
12:24:52 AM: npm run build
12:24:52 AM: ​
12:24:52 AM: Resolved config
12:24:52 AM: build:
12:24:52 AM: command: npm run build
12:24:52 AM: commandOrigin: ui
12:24:52 AM: environment:
12:24:52 AM: - NPM_FLAGS
12:24:52 AM: publish: /opt/build/repo/dist
12:24:52 AM: publishOrigin: ui
12:24:52 AM: plugins:
12:24:52 AM: - inputs: {}
12:24:52 AM: origin: ui
12:24:52 AM: package: ‘@netlify/plugin-lighthouse’
12:24:53 AM: Build failed due to a user error: Build script returned non-zero exit code: 2
12:24:53 AM: Failing build: Failed to build site
12:24:53 AM: Finished processing build request in 51.367s
12:24:53 AM: Failed during stage ‘building site’: Build script returned non-zero exit code: 2 (Search results for '"non-zero exit code: 2"' - Netlify Support Forums)

I’ve looked at the YAML, looked at everything, and I just can’t tell what’s wrong. Really stuck here - what’s going on? I reinstalled node and everything…

Looks like an issue with your Markdown than Netlify.