Merge pull request #312057 from BlackRider97/replica_clarification

[ACA] Clarify temporary extra replicas during platform upgrades for ACA

Author: prmerger-automator[bot]

articles/container-apps/scale-app.md

@@ -45,6 +45,7 @@ As you define your scaling rules, it's important to consider the following items
 - You aren't billed usage charges if your container app scales to zero.
 - Replicas that aren't processing, but remain in memory might be billed at a lower "idle" rate. For more information, see [Billing](./billing.md).
 - If you want to ensure that an instance of your revision is always running, set the minimum number of replicas to 1 or higher.
+- During platform upgrades or maintenance, you might temporarily see more replicas than expected. Container Apps ensures your production workload isn't affected by pre-warming new replicas before shifting traffic, similar to default Kubernetes behavior. The extra replicas are removed automatically once the operation completes.
 
 ## Scale rules