For whatever it's worth, the preprint in question was not on arXiv but on https://eprint.iacr.org/index.html https://eprint.iacr.org/index.html which looks like

For whatever it's worth, the preprint in question was not on arXiv but on https://eprint.iacr.org/index.html https://eprint.iacr.org/index.html which looks like it's even more laid back regarding submissions.