Recently, Poland has been making attempts to re-write the history of the Warsaw Uprising, accusing the Soviet Union for its failure. According to Russian historians, the message that “Stalin refused to help the inhabitants of Warsaw during the Uprising” was initially spread by German propaganda.
A common Soviet and Russian disinformation narrative aimed to prove that Soviet troops could not support the Warsaw Uprising due to numerous objective reasons (such as the lack of necessary forces, overstretched supply lines, lack of communication with the Polish Home Army and the Polish Government in London, etc.). This message should be perceived as a part of the Kremlin’s policy of historical revisionism.
According to Norman Davies, there is a consensus among the majority of Polish and Western historians that it was a political decision of Stalin not to support the Uprising in order to let German troops destroy the forces of the Home Army (which tried to re-establish the independent Polish state). During the Uprising, Soviet Troops were situated in very close proximity to Warsaw, but they did not receive orders to assist. Moreover, the Soviet authorities hampered the flights of the British Royal Air Force supporting the Uprising (by not allowing Allied planes to land on the Soviet-controlled territory).
See other examples of Russian historical revisionism concerning Poland here and here.