diff --git a/packages/artifact/src/internal/upload-http-client.ts b/packages/artifact/src/internal/upload-http-client.ts
index e34327010b..ad57082893 100644
--- a/packages/artifact/src/internal/upload-http-client.ts
+++ b/packages/artifact/src/internal/upload-http-client.ts
@@ -38,7 +38,7 @@ export class UploadHttpClient {
   private statusReporter: UploadStatusReporter
 
   constructor() {
-    this.uploadHttpManager = new HttpManager(getUploadFileConcurrency())
+    this.uploadHttpManager = new HttpManager(getUploadFileConcurrency() + 1)
     this.statusReporter = new UploadStatusReporter()
   }
 
@@ -112,7 +112,8 @@ export class UploadHttpClient {
       })
     }
 
-    const parallelUploads = [...new Array(FILE_CONCURRENCY).keys()]
+    // http client indices start at 1 to avoid re-using the main client
+    const parallelUploads = new Array(FILE_CONCURRENCY).fill(0).map((x, i) => i + 1)
     const failedItemsToReport: string[] = []
     let currentFile = 0
     let completedFiles = 0