Possibly Putin was honoring existing futures contracts, and even extending (on new contracts) historically lower pricing to Eastern European Nations on good terms or neutral to Russia.
Nations signing on to Biden's GloboHomo "Sanctions" would violate payment terms of those contracts.
No, I don’t think it is about “honoring” — he is on a firm legal ground, international law is already dead.
As a guess (and I’m not an economist!): he was waiting for the excess amounts of dollars and euros in Russia to be removed from the circulation... measures for this were taken immediately. The effect was stabilization of ruble (which is traded only inside Russia!) — now it is 95 to USD, up from 150.
https://www.xe.com/currencycharts/?from=USD&to=RUB
watch this chart.
BTW, the Austrians (OMV) announced that does not matter what Putin says they are going to continue paying in euros... we’ll see...