Azure ARM: deploymentScripts and first-party app identity error - azure

Question

I try to execute the current ARM template for Storage static website fonctionnality activation :
{
"type": "Microsoft.Resources/deploymentScripts",
"apiVersion": "2019-10-01-preview",
"name": "[variables('scriptName')]",
"location": "[variables('regionName')]",
// "kind": "AzurePowerShell",
"kind": "AzureCLI",
"dependsOn": [
"[resourceId('Microsoft.Storage/storageAccounts', variables('storage'))]"
],
"identity": {
"type": "userAssigned",
"userAssignedIdentities": {
"/subscriptions/<MySubscription>/resourcegroups/<MyResourceGroup>/providers/Microsoft.ManagedIdentity/userAssignedIdentities/<MyIdentityID>": {}
}
},
"properties": {
"forceUpdateTag": "[parameters('utcNow')]",
"storageAccountSettings": {
"storageAccountName": "[variables('storage')]",
"storageAccountKey": "[listKeys(variables('storage'), '2019-04-01').keys[0].value]"
},
// "azPowerShellVersion": "3.0",
"azCliVersion": "2.5.0",
"scriptContent": "[concat('az storage blob service-properties update --account-name ', variables('storage'), ' --static-website --index-document index.html')]",
"timeout": "PT2M",
"cleanupPreference": "OnSuccess",
"retentionInterval": "PT1H"
}
},
To do so, I created a new Managed Identity, and I affected Contributor role to this identity for my resource group. But during the creation of the deploymentScripts resource, it stays in 'Deploying' mode during a long time, and then failed with this error :
Exceeded maximum wait time of '00:05:00'. Message: 'First-party app identity has not become effective yet.'. (Code: DeploymentScriptOperationFailed)
I follow this guide for getting the Identity ID so I'm pretty sure the userAssignedIdentities is correct.

Answer 1

After some discussions with a Software Engineer from Microsoft, it seems that I have to wait that the Managed Identity replicates to multiple servers internally on Azure so that my scripts can found the Identity to execute properly.
I created the Managed Identity manually, waited 1 day and after that the script ran properly.