Merge pull request #74 from microsoft/psl-known-issues-readme-update

docs: add known issue in deployment guide

Author: Roopan-Microsoft

docs/DeploymentGuide.md

@@ -316,6 +316,52 @@ Follow the detailed workflow to test the migration functionality:
 
 📖 **Detailed Instructions:** See the complete [Sample Workflow](./SampleWorkflow.md) guide for step-by-step testing procedures.
 
+## Known Issues
+
+**Below are currently identified issues with workarounds. Please review before reaching out for support.**
+
+### Unable to update/add environment variables in Azure Container App
+
+You may encounter issues when attempting to modify environment variables or container configuration in Azure Container Apps:
+
+**Affected Scenarios:**
+- **App Authentication Setup:** When adding authentication-related environment variables
+- **Environment Variable Management:** Updating or deleting existing environment variables
+- **Container Configuration:** When trying to edit ACR name, image, or tag information for Container Apps
+
+**Root Cause:**
+A known issue in the Azure Portal prevents updating Container Apps configurations. This affects both environment variables and container settings.
+
+**Workaround - Use Azure CLI:**
+
+Until this issue is resolved, use Azure CLI commands to add or update environment variables and container configurations:
+
+**For Environment Variables:**
+```bash
+# Update environment variables
+az containerapp update \
+  --name <container-app-name> \
+  --resource-group <resource-group-name> \
+  --set-env-vars "KEY1=value1" "KEY2=value2"
+```
+
+**For Container Image Updates:**
+```shell
+# Update container image
+az containerapp update \
+  --name <container-app-name> \
+  --resource-group <resource-group-name> \
+  --image <registry>/<image>:<tag>
+```
+
+📖 **Detailed CLI Documentation:**
+- [Manage environment variables](https://learn.microsoft.com/en-us/azure/container-apps/environment-variables?tabs=cli)
+- [Manage revisions](https://learn.microsoft.com/en-us/azure/container-apps/revisions-manage?tabs=bash)
+
+> **Note:** This is a temporary workaround. The documentation will be updated once the Azure Portal issue is resolved.
+
+---
+
 ## Step 6: Clean Up (Optional)
 
 ### Remove All Resources