How can I consistently output a Public IP Address in an Azure Resource Manager template?

I have an Azure template that, among other things, defines a Public IP Address. I want to list that IP address in the template's output, but after the first deployment, I get an error message:

Message: Unable to evaluate template outputs: 'builderConnectionInformation'. Please see error details and deployment operations. Please see https://aka.ms/arm-debug for usage details.
Exception Details:
        Error Code: DeploymentOutputEvaluationFailed
        Message: The template output 'builderConnectionInformation' is not valid: The language expression property 'ipAddress' doesn't exist, available properties are 'provisioningState, resourceGuid, publicIPAllocationMethod, idleTimeoutInMinutes'..
        Target: builderConnectionInformation

However, if I redeploy, it shows the output I wanted just fine:

Deployment completed. Outputs:
- builderConnectionInformation = {'Username': 'ExampleAdministrator', 'Password': '<PASSWORD>', 'Public IP Address': '1.2.3.4'}

Deployment details

I'm using a Python script and calling the Azure Python SDK to deploy. The whole script is here; the relevant bits are:

    result = resource.resource_groups.create_or_update(
        parsed.group_name, {'location': parsed.group_location})

    template_params = {
        'storageAccountName': parsed.storage_account_name,
        'builderVmAdminPassword': parsed.builder_vm_admin_password,
        'builderVmSize': parsed.builder_vm_size}
    template_params = {k: {'value': v} for k, v in template_params.items()}
    deploy_params = {
        'mode': 'incremental',
        'template': template,
        'parameters': template_params}
    async_operation = resource.deployments.create_or_update(
        parsed.group_name, parsed.deployment_name, deploy_params)
    result = async_operation.result()

    msg = "Deployment completed. Outputs:"
    for k, v in result.properties.outputs.items():
        msg += f"\n- {k} = {str(v['value'])}"
    print(msg)

A representation of my template can be found here. (Note: I actually am using a YAML template, but it's converted to a Python object before being used the same way that JSON is, and it works otherwise, so I don't think that's the problem.) The relevant parts (of the converted JSON template, since that's what everyone will be familiar with) are:

{
  "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  ...
  "parameters": {
    "builderVmAdminPassword": {
      "type": "securestring"
    },
    ...
  },
  "variables": {
    "apiVersion": "2015-06-15",
    "builderVmAdminUsername": "WinTrialAdmin",
    "pubIpAddrName": "builderPubIp",
    "pubIpAddrType": "Dynamic",
    ...
  },
  "resources": [
    ...
    {
      "type": "Microsoft.Network/publicIPAddresses",
      "name": "[variables('pubIpAddrName')]",
      "apiVersion": "[variables('apiVersion')]",
      "location": "[resourceGroup().location]",
      "properties": {
        "publicIPAllocationMethod": "[variables('pubIpAddrType')]"
      }
    },
    ....
  ],
  "outputs": {
    "builderConnectionInformation": {
      "type": "object",
      "value": {
        "Username": "[variables('builderVmAdminUsername')]",
        "Password": "[parameters('builderVmAdminPassword')]",
        "Public IP Address": "[reference(variables('pubIpAddrName')).ipAddress]"
      }
    }
  }

What I've tried

I wondered if perhaps the public IP wasn't finished being allocated at the time the template deployment returns, but I didn't see a way to deal with that problem if that's what's happening - the only thing that occurred to me was to use a dependsOn property of the output, but outputs do not support a dependsOn property.

I have also found some information saying that instead of

"[reference(variables('pubIpAddrName')).ipAddress]"

I should use:

"[reference(variables('pubIpAddrName')).properties.ipAddress]"

However, that gives a similar result whether its the first time I have deployed, or any subsequent time. Here's the exact message for an initial deployment - note that it does not list ipAddress as an available property:

Message: Unable to evaluate template outputs: 'builderConnectionInformation'. Please see error details and deployment operations. Please see https://aka.ms/arm-debug for usage details.
Exception Details:
        Error Code: DeploymentOutputEvaluationFailed
        Message: The template output 'builderConnectionInformation' is not valid: The language expression property 'properties' doesn't exist, available properties are 'provisioningState, resourceGuid, publicIPAllocationMethod, idleTimeoutInMinutes'..
        Target: builderConnectionInformation

And here's the exact message from subsequent deployments - note that it does list an ipAddress property:

Message: Unable to evaluate template outputs: 'builderConnectionInformation'. Please see error details and deployment operations. Please see https://aka.ms/arm-debug for usage details.
Exception Details:
        Error Code: DeploymentOutputEvaluationFailed
        Message: The template output 'builderConnectionInformation' is not valid: The language expression property 'properties' doesn't exist, available properties are 'provisioningState, resourceGuid, ipAddress, publicIPAllocationMethod, idleTimeoutInMinutes, ipConfiguration'..
        Target: builderConnectionInformation

Summary

How can I make sure that the public IP address is always returned, even on the first deployment?