Got this email:
Your action is required to avoid potential service interruption once Amazon ECS API request validation improvements take effect on September 24, 2021. We have identified the following API requests to Amazon ECS from your account that could be impacted by these changes:
With these improvements, Amazon ECS APIs will validate that the Service and Cluster name parameters in the API match the Cluster and Service name in the ARN.
Incorrect usage, will return an error:
aws ecs describe-tasks --cluster one --tasks arn:aws:ecs:us-east-1:123456789012:task/two/48d8e8a0ccf54d969a05099a269b7528
Correct usage, clusters match:
aws ecs describe-tasks --cluster one --tasks arn:aws:ecs:us-east-1:123456789012:task/one/48d8e8a0ccf54d969a05099a269b7528
The following APIs will include request validation improvements for the following parameters:
Cluster Name Consistency Validation Only:
DeregisterContainerInstance, RegisterContainerInstance, UpdateContainerAgent, DeleteAttributes, DescribeContainerInstances, DescribeTasks, ExecuteCommand, ListTasks, PutAttributes, StartTask, StopTask, UpdateContainerInstancesState, CreateTaskSet, DeleteService, DescribeServices, UpdateService
Cluster and Service Name Consistency Validation:
DeleteTaskSet, DescribeTaskSets, UpdateServicePrimaryTaskSet, UpdateTaskSet
To avoid any service interruption from upcoming Amazon ECS API request validation improvements, please update the API requests identified above to ensure that cluster and service parameters in the API request match those in the ARN. Please refer to this page for details on these APIs. 
If you have any questions, please contact AWS Premium Support.
Will this affect Rack v2? We’re still using 20200529011310 and are a bit wary about upgrading to latest Rack v2 version, as even with the latest version we still might run into issues.
Is it time to migrate to Rack v3?