The team is aware of this issue and is working on a solution.
In the meantime, a workaround for this issue is to manually upload the document:
- On the Documents tab, click Add New, then select Document from the drop-down menu.
- Browse to and select the document that you want to add from the file system on your workstation.
- Click Open.
The document is uploaded.
For more information on adding documents to a request, see the "Adding New Documents" section in the "Adding Documents to Workfront from Your File System."