Interestingly, the USSR took a significiant part of Czechoslovakian territory after WWII, although Czechoslovakia was not at war with the USSR. On the contrary, there was a Czechoslovakian Corps fighting alongside with the Soviets at the end of WWII. These lands had not belonged to Russia before WWI, either. So what will you say? Again, your explanation will be the Germans used a lot of Czechoslovakian equipment to attack the USSR

Surprisingly, they did not ask the Czechs or Slovaks if they could use it. The Germans used French, Polish, Belgian and Dutch equipment, as well.