AWS Control Tower now helps reduce redundant AWS Config configuration items by limiting recording of global resources to home Regions only. Previously, AWS Control Tower configured AWS Config to record global resources in all Regions. Since global resources are not tied to a specific AWS Region, changes to global resources are identical across Regions. Limiting recording for global resources (such as IAM users, groups, roles, and customer managed polices) means redundant copies of global resource changes are no longer stored in every Region. This update brings resource recording into conformance with AWS Config best practices. A full list of global resources is available in AWS Config documentation.
Source:: Amazon AWS