I was able to successfully pass the test in the Cdx Validation phase, but was only able to pass the first 15 samples in the Cinematic Sound Demixing phase, and then failed the evaluation.
maybe this is related to the warning that you get about the debug mode? I am not sure where to enable the debug mode but maybe he only does a partial evaluation and then stops?!
Did you check the log files (they should appear at the end of the submission issue).
Another reason I could think of would be a timeout, i.e., if the evaluation took too long.