From testing, it appears Validation Technical Profiles are only used when added to SelfAssserted Technical Profiles
E.g the following:
<TechnicalProfile Id="ExternalIDP">
<DisplayName>Some External IdP</DisplayName>
<Protocol Name="OpenIdConnect" />
<Metadata>
<!-- ... -->
</Metadata>
<OutputClaims>
<!-- ... -->
</OutputClaims>
<ValidationTechnicalProfiles>
<ValidationTechnicalProfile ReferenceId="FETCH-MORE-CLAIMS" />
</ValidationTechnicalProfiles>
</TechnicalProfile>
does not appear to call the FETCH-MORE-CLAIMS
profile after authenticating to the external identity provider.
Is this correct, and if so, is there another way to always force a second technical profile to be called whenever a particular technical profile is called?