It is very strange, Can C# Dictionary have duplicate keys? Or is there something else, I am missing.

Here is the code

if (!StoredPoints.ContainsKey(key))
{
   StoredPoints.Add(key, new List<KafkaMessage>());
}
StoredPoints[key].Add(kafkaMessage);

I have compared the keys, both are same.
Immediate window shows that and keys are also visible in screenshot

Thanks in Advance