It’s not that surprising once you know that their goal is to be completely independent for their US for their military equipment.
It includes the nuclear bomb, missiles, fighter jet, aircraft carrier, submarines, even space capabilities (even if this last part has been lacking a bit lately).
They don’t have the US military budget but they want the same level of technology without any ties to the US.
It means that they are exporting a lot to compensate for the high investments they are pouring into military technology.
The problem is that the same companies are probably supplying Ukraine too. Ukraine is constantly playing a very finicky political game.
Edit: I was wrong, Ukraine do publish the list of the components they are finding in Russian weapons. https://war-sanctions.gur.gov.ua/en/components