Hi @Tim James ,
<<Adding the summary as answer for the benefit of broader community members who might be looking for similar information>>
Summary:
Firstly, it was a bug to have the error description as "A parameter cannot be found that matches parameter name 'ErrorId'." which was fixed here to give more meaningful error description as "output <PARAMETER> does not return the expected type <TYPE>"
Secondly, to ensure the outputs of the CUID are of type int in this case, wrapping each of the outputs with int() worked fine, and now the template test toolkit is all green as well. :)