How did you get 1956 as the end of occupation of Poland? Last German troops left this country in 1945, communist government was proclaimed in 1944 and the last Soviet soldiers left in 1992
There should be an interruption at least from 1941-1944 when the Germans occupied all of Poland. There were no Soviet troops in Poland then except for prisoners rotting away in Nazi camps.
Yugoslavia should be on this list. The Soviets captured Belgrade in 1944 after a pretty big battle with the Germans. For that matter, you could even add Italy because the Soviets occupied Trieste and the surrounding region briefly before the new Yugoslavia-Italy border was drawn up.
https://en.wikipedia.org/wiki/Landing_at_Bornholm