ECS Circuit Breaker doesn't rollback

We have deployed an ECS service with circuit breaker enabled and rollback set to True.
When tasks fail the health checks, Circuit Breaker eventually gets triggered and rollout state fails with the reason: `ECS deployment circuit breaker: tasks failed to start.`

However, it stays in this state and rollback to the previous successful deployment does not get triggered.

Deployments are done through GitHub Workflow that runs a python script

ECS agent version: 1.55.0

No repository file or test is named; begin with the GitHub Workflow and Python deployment script, then review the ECS service's circuit-breaker and rollback configuration. Reproduce a failed health-check rollout with rollback enabled and compare it with the previous successful deployment. Done means explaining why rollback is not triggered and documenting the expected ECS behavior or required service change.

Written by the indexing model from the issue text.