Event monitoring stops prematurely for nested stacks

[stitch-james]

I love the event monitoring but it seems to stop as soon as any nested stack finishes deploying. For example I get output like this (edited/simplified):

Starting event monitoring for stack: MyStack
2026-05-11T14:30:25.843Z IN_PROGRESS [CREATE_STACK: IN_PROGRESS]
2026-05-11T14:30:25.851Z [PROGRESS] AWS::CloudFormation::Stack/MyStack CREATE_IN_PROGRESS - User Initiated
2026-05-11T14:31:11.664Z [PROGRESS] AWS::CloudFormation::Stack/NestedStack1 CREATE_IN_PROGRESS
2026-05-11T14:31:14.074Z [PROGRESS] AWS::CloudFormation::Stack/NestedStack1 CREATE_IN_PROGRESS - Resource creation Initiated
2026-05-11T14:31:14.738Z [PROGRESS] AWS::CloudFormation::Stack/NestedStack2 CREATE_IN_PROGRESS
2026-05-11T14:31:15.522Z [PROGRESS] AWS::CloudFormation::Stack/NestedStack2 CREATE_IN_PROGRESS - Resource creation Initiated
2026-05-11T14:32:03.511Z [PROGRESS] AWS::CloudFormation::Stack/NestedStack1 CREATE_COMPLETE
============================================================
Deployment Summary for MyStack
============================================================
Final Status: DEPLOYMENT_COMPLETE
Total Events: 106
Errors: No errors
Duration: 122s
============================================================

In CloudFormation NestedStack2 is still being created, but as soon as NestedStack1 completes the monitoring stops. The displayed summary is for the nested stack but is incorrectly labelled as being for the parent stack. This is particularly confusing if there is an error later in the process.

Expected behaviour is for the monitoring to continue until the parent stack has completed.

To reproduce, deploy with any template that includes a nested stack.

[devvick]

Same thing happens if there are AWS::CloudFormation::StackSet resources in the template