I am trying to use Route Handler but getting a TypeError: s is not a function
Folder Structure in screenshot
Am using localisation with the [lang] folder
my one api "route"

export const dynamic = 'force-dynamic' // defaults to force-static
export async function POST(request: Request) {
    const res = await fetch(process.env.RequestBaseURL + "/customerapi/AuthUser/", {
    headers: {
      'Content-Type': 'application/json',
    },
  })
  const data = await request.json()
  return Response.json({ data })
}

getting squigly lines on Response.->json<-
type Error looks like this (full path redacted to "PATH")

TypeError: s is not a function
    at "PATH"/node_modules/next/dist/compiled/next-server/app-page.runtime.dev.js:37:5936
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async tX ("PATH"node_modules/next/dist/compiled/next-server/app-page.runtime.dev.js:37:5313)
    at async rl ("PATH"node_modules/next/dist/compiled/next-server/app-page.runtime.dev.js:38:23339)
    at async doRender ("PATH"node_modules/next/dist/server/base-server.js:1406:30)
    at async cacheEntry.responseCache.get.routeKind ("PATH"node_modules/next/dist/server/base-server.js:1567:28)
    at async DevServer.renderToResponseWithComponentsImpl ("PATH"node_modules/next/dist/server/base-server.js:1475:28)
    at async DevServer.renderErrorToResponseImpl ("PATH"node_modules/next/dist/server/base-server.js:2106:24)
    at async pipe.req.req ("PATH"node_modules/next/dist/server/base-server.js:1984:30)
    at async DevServer.pipeImpl ("PATH"node_modules/next/dist/server/base-server.js:902:25)

Google sadly isn't very helpful alsways get "page" help but not "app"