Helix Controller Does Not Rebalance Partitions After A Participant Loss

### Problem

We are using Apache Helix to distribute a resource across multiple services - all registered under the same Helix cluster name and The system is deployed on AWS ECS Fargate using Docker containers.

Each service uses the OnlineOffline state model, with 1 replica per partition and the FULL_AUTO rebalance mode.

When all services start, Helix assigns partitions as expected and all services consume their assigned partitions. The problem occurs when a service is restarted - due to an AWS Spot Termination which appear to forcefully kill the container, bypassing the logic we have to handle SIGTERM

So when a service is restarted from the cluster, the partition previously assigned to the now-stopped node are not reassigned to new live nodes. As a result, that partition remains Idle, even though other nodes are available and registered in live instances.

I have tried with both Apache Helix version 0.9.9 and the latest 1.4.3, but the problem still persists in both versions. Also When a node is removed from the cluster, there are no logs from the controller instance indicating that it is attempting to rebalance the partitions.

#### Additional Context After ZooKeeper Inspection
* /LIVEINSTANCES is perfectly listing only actively running nodes.
* But in /EXTERNALVIEW for that partition still shows the stopped node as ONLINE and does not reassign it to a live node.
* This mismatch persists even after new nodes are registered as live instances.

### Expected behavior
Helix should detect that the node is no longer live and automatically reassign its partitions to other available nodes in the cluster.

#### What worked for us

But I have been able to temporarily resolve the issue by performing a manual restart of all services register under that HELIX CLUSTER. After the manual restart, all partitions are perfectly reassigned.

I will be active here and will respond to all your replies as soon as possible and I am happy to provide any additional information or logs that would help with debugging this issue.