Thanks, eskimo. Your suggestion worked. I packaged the exact same signed app into a DMG, without rebuilding, re-signing, or changing any bundled resources. Apple accepted the submission with no issues. The same app had previously failed notarization when submitted as a ZIP. The app includes a 5.35 GB model file that required ZIP64 in the original archive, so this result is consistent with the issue you flagged. This resolves our notarization blocker. Appreciate your help!