TFT taliyah mana

when u have taliyah in TFT and have full mana when the battle starts (for ex.because of ocean buff) she starts acting really weird. First she dunno what to do - like sometimes she will wait 1 sec before attacking anyone, sometimes she will NOT cast spell but loose all her mana anyway ...her whole purpose becomes useless if she starts battle with full mana. Try it if you wanna rank down!