Assuming that Rusia is indeed in the way to apply such measures in order to stop the flight of capital off Russia, that means that they are either actually suffering from the sanctions (more than they would like to admit) or they are preparing themselves to live with a cut of their income in the long run.
I assume the second scenario is more likely, keeping in mind Russia still have some economical allies and the price of fuels is high.
I think this is done to maximize the rejection of dollar support. This is Russia's new policy after the freezing of their foreign assets. Now the emphasis is on the national currency and the currency of the allied states. Refusal to pay debt obligations in dollars already speaks volumes. Instead, the payment went in the national currency.