is alter ult bugged or some**bleep**?

i cant take the **bleep**ing alter ult on the first go it just keeps cancelling after channelling half way??? i dont **bleep**ing get it why it keeps cancelling by itself? what is happening ive just lost an easy win from this stupid **bleep** **bleep**ing bug? surely i cant be the only one who keeps getting cancelled on using the ult ??? what the actual