This is working as intended, Ukraine attacks refineries, which makes it necessary for Russia to export crude oil at lower prices.
This way Ukraine can hit the Russian economy, without causing oil prices to increase on the global market, something Ukrainian allies have expressed concern about.
It is allegedly already causing difficulties for Russia to refine enough oil for their needs for their war against Ukraine, and that makes it necessary for Russia to export crude oil and buy some of it back at higher prices after it has been refined.