Despite my belief that this is more of a bug than a feature request, as it is contrary to the documentation here: https://documentation.solarwinds.com/en/success_center/swsd/content/completeguidetoswsd/process_integration.htm, my associated support case on this has ended with the advice to submit this as a feature request.
If you try to use {{user-var.user.id}} in the URL field of a process integration, you get the first listed group ID of the user instead of the actual user ID. In fact, no matter WHAT attribute of the user variable you put in the URL field, you'll get the first listed group ID of the user, not their ID. You can use {{user-var.email}}, just {{user-var}} or {{user-var.id}}. All of them will return the first listed group ID of the associated user. I'm not really sure how this is a feature request and not a bug, but I'm submitting here as advised.
As long as I'm documenting this, it doesn't seem logical that {{user-var.id}} should resolve to the group ID of the user, as documented. Despite being illogical, I'm not sure how this is even useful or predictable, as a user can have many groups, so it's rather arbitrary to just pick the first group ID of the user, and return that as {{user-var.id}}. Logic would dictate that this variable should clearly resolve to what it looks like it should - the ID of the user.
I would also suggest that the documentation at the aforementioned link be revised, as it is at least partially wrong. It states that {{user-var.user.id}} can be used as a variable to resolve to the user ID of a user field. This is at least partially incorrect. This is not true when used in the URL field of a process integration, so the documentation is at best misleading, if not simply inaccurate if this isn't a bug. It should be noted that {{user-var.user.id}} DOES resolve to the correct value (the user ID of the user) when used in the BODY of the request, just not when used in the URL field.
A common use case would be to update a user object (one that is selected in a field on a service request) as a result of conditions, process, and/or data in a service request. It requires use of the associated userid you want to update in the URL of the SWSD API process integration. Due to this bug (or "lack of feature"), this is not possible.
More details and screenshots can be found in a forum discussion on this topic here:
https://thwack.solarwinds.com/product-forums/solarwinds-service-desk-swsd/f/forum/93827/variables-in-process-integration-do-not-work-as-expected
