This page will contain some information about how "pending" pacts work. This is feature is in beta testing but should be released soon. It aims to prevent changed pacts breaking provider builds, while ensuring that provider tests still correctly fail when they break backwards compatiblity.
You can read about the feature here. http://blog.pact.io/2020/02/24/how-we-have-fixed-the-biggest-problem-with-the-pact-workflow/