N.N. Soyko in "Dvoohmyestnyi istriebitiel DI-6" stated that information about operationally using DI-6 over Khalkhin Gol is only the legend. This same about Winter War and Great Patriotic War.
During Winter War there were a little DI-6, but they were used in training role and speed liaison aircraft.
To the Great Patriotic War lasted single DI-6, where of most unairworthy.
There are mentions about using of DI-6 at Leningrad Front as the false aim at airfields. 6th ShAP of Leningrad Front has only 1 DI-6 at Maysniemi aifield not far from Vyborg.