MarkPerry-2079, Thanks for the follow-up and sharing additional info.
As for as managing the feature - By default, all your traffic is routed to the production slot (100%). By setting the traffic percentage to 10% on the staging slot. Then click Save. With that simple change, a tenth of your production traffic will now go to the new build.
You add a % of the traffic to route to other slots thus distributing the traffic. The feature allows you to route production traffic to one of those deployment slots.
To investigate this further, I would need your WebApp and subscription details (PII data), for this I'll reach out you privately.
PS: Please do not share any PII data on the public forum.