ContinueOnError attribute has no effect on ValidationTechnicalProfile

Question

I am working on a reset password user journey using Azure AD B2C custom policies. I have a requirement for the new password to be different from the user's last password, so I started using the sample provided for this scenario (https://github.com/azure-ad-b2c/samples/tree/master/policies/password-reset-not-last-password).

I noticed for this policy you have to enter your old password, this is not much use if a user has forgotten their password as they cannot confirm their old password.

I am trying to adapt this to run the login-NonInteractive-PasswordChange technical profile using the newPassword field, rather than the oldPassword. This technical profile uses the ROPC flow to authorise the user using their username and password (now using newPassword instead of oldPassword). I am then checking if the authentication was successful with the newPassword, if it is successful then we can infer that their new password is the same as their old password, if the authentication fails then the new password is different and therefore valid.

This all seems to be working but I cannot seem to move on with my ValidationTechinicalProfiles when the ROPC authorisation returns a 400 response, I have included the attribute ContinueOnError="true" but it is not continuing, instead I just get a message saying "The username or password provided in the request are invalid."

Any suggestions for this issue would be greatly appreciated, thanks!