An American tech company used an AWS CloudFormation template to deploy its static corporate website hosted on Amazon S3 in the US East (N. Virginia) region. The template defines an Amazon S3 bucket with a Lambda-backed custom resource that downloads the content from a file server into the bucket. There is a new task for the DevOps Engineer to move the website to the US West (Oregon) region to better serve its customers on the West Coast with lower latency. However, the application stack could not be deleted successfully in CloudFormation. Which among the following options shows the root cause of this issue, and how can the DevOps Engineer mitigate this problem for current and future versions of the website?