title: Can't create a SNS Event source on a Lambda function using CloudFormation
body: <p>This is the <em>Cloudformation</em> template code related to my problem: </p>
  
  <pre><code>"SNSTopic": {
    "Type": "AWS::SNS::Topic",
    "Properties": {
      "TopicName": "JumpboxPresenceTopic",
      "DisplayName": "Jumpbox Presence Topic",
      "Subscription": [
        {
          "Endpoint": {
            "Fn::GetAtt": [
              "Lambda",
              "Arn"
            ]
          },
          "Protocol": "lambda"
        }
      ]
    }
  },
  "Lambda": {
    "Type": "AWS::Lambda::Function",
    "Properties": [...]
  </code></pre>
  
  <p>I can see the topic in the <em>SNS</em> dashboard:
  <a href="https://i.stack.imgur.com/N0W85.png"><img src="https://i.stack.imgur.com/N0W85.png" alt="enter image description here"></a></p>
  
  <p>But it does not display in the lambda function <em>Event Sources</em> panel:
  <a href="https://i.stack.imgur.com/KlFUT.png"><img src="https://i.stack.imgur.com/KlFUT.png" alt="enter image description here"></a> </p>
  
  <p>The weird thing about this, is that if I create a new subscription from the <em>SNS</em> dashboard for that same lambda function, no new subscription is created since it would be an exact duplicate. However, now if I check the <em>Event Sources</em> panel in the <em>Lambda dashboard</em>, I can see a new entry for the <code>SNS: JumpboxPresenceTopic</code>: 
  <a href="https://i.stack.imgur.com/NbzIs.png"><img src="https://i.stack.imgur.com/NbzIs.png" alt="enter image description here"></a></p>
  
  <p>I feel like it's an issue on Amazon's side but I could be wrong. Is there something wrong with my approach or is it a limitation of AWS ?</p>