Commentary for Bava Batra 271:8

The time on the deed. For it is written at its beginning such and such day of Shabbat, Ploni asked us to witness and make an act of acquisition from me to Ploni my son, after my death.

It supports it. That from time the gift started, for if you say otherwise, then the time in the deed was written for naught. But certainly it was written to tells us that it was acquired on that day. And thus the Halakha is according to Rav Yossi, for if he writes that he acquires it after death even though he does not write from today, for Rav says that the Halakha is according to Rav Yossi. And even though it is written in Gittin 85b, Rav made a ruling that divorces take effect when handed over, to exclude Rav Yossi who says it takes effect on the date on the deed. But it was not stated explicitly there in Gittin that Rav changed his mind from that which he stated that the Halakha is according to Rav Yossi. But because it says that he made a ruling, it means that regarding divorces, since it does not involve an acquisition, for that reason he made a ruling to be more flexible because of the strict nature of sexual restrictions. But with regards to financial matters the Halakha is according to Rav Yossi. For one can say that Rav only said that the Halakha is according to Rav Yossi only for deeds that involve an acquisition. ...