ADB2C Custom policy user journey - override the content definition of each orchestration step

I have a custom policy which I am setting up which is based 2 steps in the user journey

1. Sign in signup unified
2. Self assert page.

In my RP file, I have specified ContentDefinitions for each 'type' of page so I can override these with my own. From my understanding, as the RP file is the last one point in the hierarchy, it will override always.

What I am finding is that it works for step 1, but step 2 always seems to default to the standard Microsoft page.

e.g. RP file.

<ContentDefinitions>

  <!--For step 1-->
  <ContentDefinition Id="api.signuporsignin">
    <LoadUri>https://MYURL/custom_step1.html</LoadUri>
    <RecoveryUri>~/common/default_page_error.html</RecoveryUri>
    <DataUri>urn:com:microsoft:aad:b2c:elements:contract:unifiedssp:1.2.0</DataUri>
    <Metadata>
      <Item Key="DisplayName">Signin</Item>
    </Metadata>
  </ContentDefinition>

  <!--For step 2-->
  <ContentDefinition Id="api.selfasserted">
    <LoadUri>https://MYURL/custom_step2.html</LoadUri>
    <RecoveryUri>~/common/default_page_error.html</RecoveryUri>
    <DataUri>urn:com:microsoft:aad:b2c:elements:contract:selfasserted:1.2.0</DataUri>
    <Metadata>
      <Item Key="DisplayName">Collect information from user page</Item>
    </Metadata>
  </ContentDefinition>

</ContentDefinitions>

Ive seen on my UserJourney that Step 1 also seems to define a ContentDefinition (a default I guess?) but specifying my own one on each step didn't seem to have any effect either.

<OrchestrationStep Order="1" Type="CombinedSignInAndSignUp" ContentDefinitionReferenceId="api.signuporsignin">

Suggestions appreciated!