Intermittent fetch cache failing build on seemingly succesful request

[NicholasG04]

Sometimes, but often repeatably for a period of time (unsure why), our fetch calls fail at build time. The error message seems to imply the data is being returned fine, so can't understand why this only happens occasionally. Thanks.

┌──────────────────────────────┐
│ OpenNext — Generating bundle │
└──────────────────────────────┘

Bundling middleware function...
Bundling static assets...
Bundling cache assets...
undefined:1
{"kind":"FETCH","data":{"headers":{"accept-ranges":"bytes","alt-svc":"h3=\":443\"; ma=2592000,h3-29=\":443\"; ma=2592000","apicdn-cache-control":"public, max-age=60, s-maxage=3600, stale-while-revalidate=60, stale-if-error=3600","cache-control":"public, max-age=60, s-maxage=60, stale-while-revalidate=15, stale-if-error=3600","content-encoding":"br","content-length":"187","content-type":"application/json; charset=utf-8","date":"Tue, 29 Apr 2025 19:26:15 GMT","sanity-gateway":"k8s-gcp-us-e4-prod-ing-02","sanity-query-hash":"X1GR0w26rA4 nyN2XmeKrzc","server-timing":"api;dur=7","strict-transport-security":"max-age=63072000; includeSubDomains; preload","vary":"accept-encoding, origin","via":"1.1 google","x-sanity-age":"0","x-sanity-shard":"gcp-eu-w1-01-prod-1034"},"body":"eyJyZXN1bHQiOlt7ImN1cnJlbmN5Y29kZSI6IkVVUiJ9XSwicmVzdWx0U291cmNlTWFwIjp7ImRvY3VtZW50cyI6W3siX2lkIjoiZmVlNDU0MmItMzA4NC00OTY4LWEyOWYtY2NhMTM3NGFkMDJjIiwiX3R5cGUiOiJyZWdpb24ifV0sInBhdGhzIjpbIiRbJ2N1cnJlbmN5Y29kZSddIl0sIm1hcHBpbmdzIjp7IiRbMF1bJ2N1cnJlbmN5Y29kZSddIjp7InNvdXJjZSI6eyJkb2N1bWVudCI6MCwicGF0aCI6MCwidHlwZSI6ImRvY3VtZW50VmFsdWUifSwidHlwZSI6InZhbHVlIn19fSwic3luY1RhZ3MiOlsiczE6U0QzeW1RIl0sIm1zIjoxfQ==","status":200,"url":"**REMOVED**","revalidate":86400,"tags":[]}]}

SyntaxError: Unexpected token ] in JSON at position 1473
    at JSON.parse (<anonymous>)
    at file:///home/runner/.npm/_npx/d1d80c683aba60d6/node_modules/@opennextjs/aws/dist/build.js:432:39
    at file:///home/runner/.npm/_npx/d1d80c683aba60d6/node_modules/@opennextjs/aws/dist/build/helper.js:118:13
    at Array.forEach (<anonymous>)
    at traverseFiles (file:///home/runner/.npm/_npx/d1d80c683aba60d6/node_modules/@opennextjs/aws/dist/build/helper.js:111:51)
    at createCacheAssets (file:///home/runner/.npm/_npx/d1d80c683aba60d6/node_modules/@opennextjs/aws/dist/build.js:430:13)
    at build (file:///home/runner/.npm/_npx/d1d80c683aba60d6/node_modules/@opennextjs/aws/dist/build.js:56:11)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async file:///home/runner/.npm/_npx/d1d80c683aba60d6/node_modules/@opennextjs/aws/dist/index.js:9:1

[khuezy]

Can you open the build.js file and look at line 432?
https://github.dev/opennextjs/opennextjs-aws/tree/main/packages/open-next/src/helpers

It looks like it's trying to parse JSON of a file?

Are you running multiple builds at once that may wipe some of the .json files?