Sett and Hecarim ultimate interaction glitch

I'd like to report a glitch on Sett that hapenned yersteday in ranked. I got ganked by Hecarim and while he ran on me with his E + R, I spammed my ultimate to survive. The interaction between the two ults was confusing and after my R, I could only activate my Q spell. Sett's W and E wouldn't cast, I tried reseting the controls, I tried using spells without quick cast using my mouse but nothing worked. His kit went back to normal after I used ultimate again.

The replay expired I don't have video proof, hope it still helps. Have a nice day everyone.