Can't use a ArtifactPath for template configuration in CloudFormation + CodePipeline

[mindstorms6]

Hi friends!

I have a cdk CFN action that tries to do:

    new CreateReplaceChangeSet(stack, 'BuildChangeSetProd', {
      stage: prodStage,
      stackName,
      changeSetName,
      role: changeSetExecRole,
      templatePath: new ArtifactPath(buildAction.artifact!, 'template.yaml'),
      templateConfiguration: new ArtifactPath(buildAction.artifact!, 'templateConfig.json')
    });

When running this however during synth - the CDK gets very upset with me saying

test.cloudformation-pipeline-actions.js
✖ CreateChangeSetAction can be used to make a change set from a CodePipeline                                                                                                                                                                                                                  While synthesizing MagicPipeline/Resource: Trying to resolve() a Construct at /stages/2/actions/0/configuration/TemplateConfiguration/artifact
    --- resource created at ---                           
at new Pipeline (/Users/brelandm/repos/aws-cdk/packages/@aws-cdk/aws-codepipeline/lib/pipeline.ts:22:4)
at Object.CreateChangeSetAction can be used to make a change set from a CodePipeline (/Users/brelandm/repos/aws-cdk/packages/@aws-cdk/aws-codepipeline/test/test.cloudformation-pipeline-actions.ts:18:22)
at Object.<anonymous> (/Users/brelandm/repos/aws-cdk/node_modules/nodeunit/lib/core.js:236:16) 
at /Users/brelandm/repos/aws-cdk/node_modules/nodeunit/lib/core.js:236:16

Which, I'm not sure what that means TBH.
Oddly, removing the last line fixes it though :

templateConfiguration: new ArtifactPath(buildAction.artifact!, 'templateConfig.json')

Even though the line above it is effectively the same.

I'm adding a test now - any thoughts on what this message is telling me and how to deal with it?

[mindstorms6]

JK!
Wrote a test and a fix is incoming.