Warwick ULT UNWANTED CAST

If warwick is in his E and attempts to cast ulti, the ult will not cast at that time but instead autocast after his E has worn off. The same thing will happen if warwick is in a hold and attempts his ult. I'm also using Quick cast with no cast indicators. I Just feel that if WW's ult fails to cast initially then it shouldnt force/auto cast it as soon as E or the hold wears off.