SIGN_REQUEST.COMPLETED not firing webhook v2

Hi,

I am creating a Sign Request via API and cannot get the webhook to fire when the signature is added.

Through the API, here is what happens:
1. First the document is uploaded
2. A Sign request is then created
3. A v2 webhook is created on the file ID from from the Sign Request response (initially this was on the document upload ID, but that didn't work either).

All responses come back fine, and I can see the document show up in the 'admin content' view on the website. At this point, there is the original uploaded file, and a new file with (1) on the end of the filename.

When the signature is added, the 'admin content' shows multiple versions (all showing as created by BoxSign), a few minutes apart (currently 15 on my last test document).

The webhook that was registered does not fire at all throughout this process.

If i download the file in the admin console, the webhook fires (as I registered multiple events on the webhook) - so it works within the app, but not the 'completed' one after a single signature.

What am I doing wrong?

Regards,
Matt