Vouch parameter preventing processing?

[gRegorLove]

I've noticed this a few times with different sites using webmention.io:

My automatic Webmention sending includes a vouch parameter and I get an HTTP 303 response with "Status: Pending" body, but it never seems to process. I'll use the URL https://webmention.io/api/mentions.jf2?target= to check if it's in the list of mentions for the target some time later and it isn't there. Then I'll usually use the form to manually re-send it (e.g. https://webmention.io/martymcgui.re/webmention) and it goes through within seconds.

This happened again about 15 minutes ago with this post. A bit later I used the form on the original post to submit and it showed up in seconds. The vouch parameter seems to be the only difference I can tell between the requests.

I don't have the webmention.io status URL for the automated WM, but the response body was HTML with:

Status: Pending
source  https://gregorlove.com/2023/02/welcome-back/
target  https://francescoschwarz.com/notes/2023-02-13-16-25-33
The webmention is currently being processed

Debug Info
{ "status": "pending", "source": "https://gregorlove.com/2023/02/welcome-back/", "target": "https://francescoschwarz.com/notes/2023-02-13-16-25-33", "private": false, "summary": "The webmention is currently being processed", "data": { } }

The status URL for the successful WM via Francesco's form: https://webmention.io/francescoschwarz.com/webmention/XeopId-EWNC_jOQfLPNp

Edit: the automated webmention parameters from my site:

source=https%3A%2F%2Fgregorlove.com%2F2023%2F02%2Fwelcome-back%2F&target=https%3A%2F%2Ffrancescoschwarz.com%2Fnotes%2F2023-02-13-16-25-33&vouch=https%3A%2F%2Fgithub.com%2FgRegorLove

[aaronpk]

There is currently nothing in webmention.io that touches a vouch parameter, so I'm really not sure what to say here. Even when it calls out to XRay, it builds its own request so vouch is not part of that either.