Symfony import of YAML files losing bit chomping indicators

I am using a plugin for Grav CMS in conjunction with symfony/twig to import a yaml file with the following contents:

sp:
  xyzsp:
    description: ''
    issuer: https://ssotest.com
    relay_state: "/"
    login_url: https://ssotest.com
    logout_url: https://ssotest.com/access/logout
    slo_url: ''
    metadata: >-
      <?xml version="1.0" encoding="UTF-8" standalone="yes"?><EntityDescriptor entityID="your_subdomain.com" xmlns="urn:oasis:names:tc:SAML:2.0:metadata"><SPSSODescriptor AuthnRequestsSigned="false" WantAssertionsSigned="true" protocolSupportEnumeration="urn:oasis:names:tc:SAML:2.0:protocol"><NameIDFormat>urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress</NameIDFormat><AssertionConsumerService index="1" Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" Location="https://accountname.com/access/saml"/></SPSSODescriptor></EntityDescriptor>
    sign_response: false
    sign_assertion: true
    encrypt_assertion: false
    profile:
      assertion: global
      nameid: global
      attribute: empty
      response: global
      signature: global

I am creating an array and then using yaml_emit to import the full YAML file:

{% autoescape 'html' %}
{{ arr2|yaml_emit}}
{% endautoescape %}

This works for the most part. However, on the web page, the imported file is rendered without the >- block chomping indicator for the 'metadata' field, so it is rendered as:

sp:
  xyzsp:
    description: ''
    issuer: https://ssotest.com
    relay_state: /
    login_url: https://ssotest.com
    logout_url: https://ssotest.com/access/logout
    slo_url: ''
    metadata: <?xml version="1.0" encoding="UTF-8" standalone="yes"?><EntityDescriptor entityID="your_subdomain.com" xmlns="urn:oasis:names:tc:SAML:2.0:metadata"><SPSSODescriptor AuthnRequestsSigned="false" WantAssertionsSigned="true" protocolSupportEnumeration="urn:oasis:names:tc:SAML:2.0:protocol"><NameIDFormat>urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress</NameIDFormat><AssertionConsumerService index="1" Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" Location="https://accountname.com/access/saml"/></SPSSODescriptor></EntityDescriptor>
    sign_response: false
    sign_assertion: true
    encrypt_assertion: false
    profile:
      assertion: global
      nameid: global
      attribute: empty
      response: global
      signature: global

How can I ensure the block chomping indicator is not removed?