Warwick cannot use Q after his R is interrupted

When i use Warwick, sometimes, after my R was interrupted, i cannot use Q immediately. It seems like i could not use it until my R's time pass. For example, when i use R on others in the first sec, then my R was interrupted in the second sec, after that, i could not use Q in next few sec. And i found a lot of people report it before, but it was still not be fixed. OR, if Warwick cannot use Q immediately after his R was interrupted, please add it in the explanation of his skills. Thank you!