Query regarding the upload of multiple files in different browsers in Angular (inconsistent behaviors)

Question

In my Angular project, I have a simple multiple file upload:

<input
  type="file"
  class="display-none"
  #file
  (change)="onFilesSelectedForUpload()"
  onclick="value = null"
  multiple
/>

Based on some investigations, most browsers (Chrome, Firefox, Edge) have a limit of 6 connections per hostname reference and I was expecting the same behaviour from them, but it did not happen.

• Chrome

When there are 6 files being uploaded (each with a size of 100 MB), and I try to access the list of groups, the last request is not processed and it stays in pending status. The screenshot shows what the Network tab looks like -> Check Image Here

But when a file is successfully uploaded, and the number of files in progress goes to 5, then the request is processed and the list of groups is displayed.

• Edge

I repeated the same scenario using Microsoft Edge and I encountered the same behavior.

• Mozilla Firefox

Using Mozilla, I observed an unstable behavior. When I upload the same 6 files, the next request (to display the list of groups) is not processed. In the first test, groups are displayed when there were 5 files in progress, in the second test only when there was only 1 file in progress, and in the third test when there were 4 files in progress.

I would highly appreciate your help with any information on why this is happening and what could be the possible cause.

Thank you.