Your own air defence "the worst enemy" of Russian aviation?

In the context of the fresh Ukrainian attack on the Engels-2 strategical bomber base under Saratov, the news came out – unconfirmed for now – that the Russian air defence consequence shot down its own Su-27 fighter at the same time. Whether or not this information is confirmed, the Russian infosphere has interesting opinions that Russian air defence is liable for the "most of the shootings" of Russian aircraft of the latest types.