File Upload on apollo gateway

Question

I have two graphql subgraphs server a and server b. Each running fastify and mercurius and using grapqql-upload to handle files. I also have an apollo gateway connected to both servers and working well for queries and mutations. However when using file upload I get a validation error. Anyone ever dealt with this ? Do I need to process the uploaded file in both the gateway and the subgraphs

I have tried processing the file on both the gateway and the subgraph as well as only on the subgraph and on only on the gateway using

app.addHook("preValidation", async (req, res) => {
    if (
      !req.headers?.["content-type"]?.includes("multipart") ||
      req.url !== "/graphql"
    ) {
      return;
    }
    const body = await processRequest(req.raw, res.raw);
    console.log(body);
    req.body = body;
  });

however i'm still unable to upload files i run into graphql validation error