How do we troubleshoot connection failure after MemoryDB primary node failover

My team have had issues using StackExchange.Redis's client for C# with MemoryDB:
https://stackoverflow.com/questions/72545009/connection-to-aws-memorydb-cluster-sometimes-fails

We've also written to StackExchange.Redis' github here:
https://github.com/StackExchange/StackExchange.Redis/issues/2013

In short, the issue is that when we manually failover MemoryDB while having 2 or 3 nodes (1 primary, 1 or 2 replicas, 1 shard), we're unable to reach the MemoryDB cluster via the cluster endpoint unless we restart the ECS task (or reconnect using ConnectionMultiplexer).

We've found that if we do:

foreach (var endpoint in connectionMultiplexer.GetEndPoints(false))
{
  Console.WriteLine(endpoint.ToString());
}

We only get back the cluster endpoint. But our understanding is that it should be returning all discovered nodes.

Is there anything we can do to further debug this issue?