When the new matrix is created, before the ISOs exist, the OpenQa Trigger does not recognize it, and instead of fail-ending it updates the "last_tested" data, and ends. Trigger should recognize, when (any of the) ISOs fails to download, and should not update the persistent data accordingly.
This issue has been migrated to Fedora Forge: https://forge.fedoraproject.org/quality/fedora_openqa/issues/2
Please continue any further discussion there.