The tenure of Sergun's successor, Igor Korobov, was marked by what some news media construed as multiple high-profile setbacks, such as the thwarted 2016 coup d'état attempt in Montenegro, the failed 2018 Salisbury poisoning, and an unprecedented number of disclosed GRU agents. Korobov died on 21 November 2018, "after a serious and prolonged illness", according to the official Defence Ministry statement. His death provoked speculations and unverified reports of him having fallen ill in October that year following a harsh dressing-down from President Vladimir Putin. However, former CIA station-chief Daniel Hoffman cautioned in 2017 that some of the Russian intelligence's recent operations that appeared to be botched might have been intended for discovery. Similarly, in 2019, Eerik-Niiles Kross, a former Estonian intelligence official, opined that GRU's apparent sloppiness "has become part of the psychological warfare. It's not that they have become that much more aggressive. They want to be felt. It's part of the game."