"Failed to load" error with attachments uploaded via Forms

Summary

Users uploading files to Forms configured with multiple attachment fields are experiencing issues in which the thumbnails on the submitted Forms are displaying "Failed to load".

From internal investigation

... might be caused by user uploading multiple attachments to multiple attachment fields in a proforma form and then aggressively clicking the submit button. This causes a data loss because the form is submitted without all the files successfully uploading the media service ...

Steps to reproduce

• Create Form with at least two attachment fields and link to request type visible in portal
• Access the form via the portal and upload files to each attachment field
  • Best reproducible using file that is at least 10MB
• Click Send as soon as the button is active

Expected result

Attachments uploaded to ticket.

Actual result

Thumbnails for attachment in both portal/issue view displaying "Failed to load".

Workaround

Upload file as comment after ticket is created