Zyra ult bug

I never thought this was a bug but if the anivia Q was considered a bug then it goes the same with zyras ult. When i first started playing her I would accedentally click the ult to be like 1-10 units out of range and she wouldnt walk to go do it. so it would mess up my combo and i would get all flustered trying to figure it out and die. I never thought it was a bug just the way it was supposed to be, but if anivias Q does the same thing maybe it is a bug. If this could be fixed or explained i would really appreciate it Please and thank you