The Soviet leadership had good reasons to be suspicious about the allies. After all, Western powers had shown hostility to the Soviet from the outset of the Russian revolution, by supporting tsarist troops, sending armies, even bombing Russia by air.<quoted text>
And of course the Soviets were innocent and wouldn't think of shooting down an Avro Lincoln or a Swedish Dakota etc would they.
I've just finished reading 'Tirpitz' and the Soviets were paranoid with the western allies even when we were sending them aid with the arctic convoys. Winston Churchill had to virtually jump through hoops to get British aircraft based in Soviet territory to defend the convoys from air and sea attack.
Later, the West supported the counter-revolution during the civil war, up to 1923. The West backed Poland in the war against the USSR, etc...
The Soviet Union was diplomatically alienated, not recognised at the League of nations.
When the NAZI threat came about, France and Britain refused Stalin's offer of an alliance against Germany.
So, it's no surprise that, when the tables turned, the Soviet weren't so keen on their Western allies. Most of their officers, commissars and members of the Politburo had faced Western hostility for 20 years!