Flame breath cancelling when using mouse left click

I am playing flame breath pathfinder, when I press flame breath and keep it pressed and click to move with mouse without the attack without moving or with it it cancels the flame breath, the only way i managed it to work is not using my mouse for moving and just wasd. Also when the flame breath cooldown finishes then and i keep casting , when i ran out of mana the cooldown starts over but i can still cast without having annimation of the flame that comes out of the wyvern. thank you