EKS Auto Mode automatically terminates empty nodes

While monitoring an EKS upgrade, I noticed an empty node vanishing on its own. At 22:09:17 there were 4 nodes, but by 22:10:51 the one with no pods (i-0e0b6da9f0dda191c) had been terminated — no manual intervention.

---22:09:17---  (4 nodes, 1 empty)
i-0a797512240b8a78d   v1.34  ← has nginx pods
i-0c1a5101ad5cdfaac   v1.34  ← has nginx pods
i-0e0b6da9f0dda191c   v1.34  ← no pods
i-0f1976563dcc3e932   v1.34  ← has nginx pods
 
---22:10:51---  (3 nodes, empty one gone)
i-0a797512240b8a78d   v1.34
i-0c1a5101ad5cdfaac   v1.34
i-0f1976563dcc3e932   v1.34

The events log showed DisruptionTerminating: Disrupting Node: Empty. This is Karpenter's consolidation feature running under the hood of EKS Auto Mode — it terminates unneeded nodes for cost optimization. Expected behavior, but seeing a node disappear from your monitoring logs for the first time is a bit startling.