KeyVaultForLinux v2.0 does not download CA chain

[Key Vault docs](https://docs.microsoft.com/en-us/azure/virtual-machines/extensions/key-vault-linux) says that version 2.0 downloads CA chain, but it doesn't

Extension info
```
{
"autoUpgradeMinorVersion": true,
"enableAutomaticUpgrade": null,
"forceUpdateTag": "*****",
"id": "/subscriptions/*****/extensions/KeyVaultForLinux",
"instanceView": null,
"location": "*****",
"name": "KeyVaultForLinux",
"protectedSettings": null,
"provisioningState": "Succeeded",
"publisher": "Microsoft.Azure.KeyVault",
"resourceGroup": "*****",
"settings": {
"secretsManagementSettings": {
"observedCertificates": [
"my cert"
],
"pollingIntervalInS": "30",
"requireInitialSync": true
}
},
"suppressFailures": null,
"tags": null,
"type": "Microsoft.Compute/virtualMachines/extensions",
"typeHandlerVersion": "2.0",
"typePropertiesType": "KeyVaultForLinux"
}
```

If I download certificate from Azure Portal (PEM format) I get one file with cert/private key/CA chain.
But Key Vault extension syncs only cert/private key without CA chain.