In March 2022, he gained notoriety for displaying a pro-invasion Z symbol during a medal ceremony, shortly after the beginning of the Russian invasion of Ukraine.

[1] In 2019 Kuliak became the Russian Junior all-around and floor champion and the silver medalist on horizontal bar.

In March 2022, Kuliak wore a "Z" sticker on his chest during the medal ceremony of the parallel bars competition at the 2022 FIG Artistic Gymnastics World Cup series in Doha.

[3] "Z", a letter which is not part of the Cyrillic alphabet, is a tactical marking used by Russian invading forces in Ukraine.

Kuliak displayed the symbol while standing on the podium next to a Ukrainian athlete, Illia Kovtun, who won the event.