I somehow had 2019 in my mind and it seems that my memory did not trick me.
Obviously FIVB initially sent a letter to Brazilian Federation with the wrong date and corrected it now. Leal will be allowed to play for Brazil only from April 2019
source: https://globoesporte.globo.com…ir-de-abril-de-2019.ghtml
Yeah, I thought 2019 as well, but then the news came out - as well as FIVB's screw up. So it's indeed April 2019 for Leal.