No it was not working before certification and not working now as well.
Even from Windows or Mac, it is not working showing the same error as posted.
We cannot attach file here. However if you download the their given test package and extract the zip and navigate the folder structure as . ccda-uscdi-certification-testdata-main --> uscdi-v3-testdata --> Receiver SUT Test Data --> 170.315_b1_ToC_Amb and use the two zip files, you will be able to reproduce the same error.
You can see below screenshot of folder navigation and the selected zip files used, which gives error.