Conditions:
  IsUsEast1: !Equals [!Ref 'AWS::Region', 'us-east-1']
  IsUsWest2: !Equals [!Ref 'AWS::Region', 'us-west-2']
Resources:
  # Doesn't fail on normal process
  StackNormal:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: ./stack_nested.yaml
      Parameters:
        One: a
        Three: b
  # Doesn't fail on scenarios
  Stack3:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: ./stack_nested.yaml
      Parameters:
        Fn::If:
        - IsUsEast1
        - Zero: a
          One: b
        - Fn::If:
          - IsUsWest2
          - Two: c
            Three: d
          - One: e
            Three: f
