Cloudflare R2 Worker throwing 'Network Connection Lost' error

In my worker I am converting a base64 string I get from the request to a blob with some function. However, when I try to PUT the blob into my bucket, I get "Network Connection Lost" error. I can successfully PUT just the base64 string or any other string but not a blob. Here is my worker:

// Function to convert b64 to blob (working fine)
function b64toBlob(b64Data, contentType, sliceSize=512) {
  const byteCharacters = atob(b64Data);
  const byteArrays = [];

  for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
    const slice = byteCharacters.slice(offset, offset + sliceSize);

    const byteNumbers = new Array(slice.length);
    for (let i = 0; i < slice.length; i++) {
      byteNumbers[i] = slice.charCodeAt(i);
    }

    const byteArray = new Uint8Array(byteNumbers);
    byteArrays.push(byteArray);
  }

  const blob = new Blob(byteArrays, {type: contentType});
  return blob;
}

export default {
  async fetch(request, env) {
    const url = new URL(request.url);
    const key = url.pathname.slice(1);

    switch (request.method) {
      case 'PUT':
        const contentType = 'application/pdf';
        const b64Data = request.body;
        
        const blob = b64toBlob(b64Data, contentType);

        try {
          await env.qa_sub_agreements_bucket.put(key, blob, { // Failing here
            httpMetadata: request.headers,
          })
          return new Response(blob) // Successfully returns the blob when above PUT is commented out
        } catch (e) {
          console.error(e.message, e.stack); // Logs out "Error: Network Connection Lost"
        }