EO 13818 was signed on December 20, 2017 and took effect in shortly after midnight at 12:01 a.m. on December 21, 2017. It was NOT signed on December 21, 2017
https://www.whitehouse.gov/presidential-actions/executive-order-blocking-property-persons-involved-serious-human-rights-abuse-corruption/
https://www.treasury.gov/resource-center/sanctions/Programs/Documents/glomag_eo.pdf