I'm a bit baffled at how you are using Stalk twice in a row without a Gibbet or Gallows in between. There's a 1 second recast on Stalk so you can't weave it with itself even by accident, so you'd have to grossly clip your GCD to even attempt this. It sounds like a worrying skill issue.

You'll probably see this as less of an issue after you've had a bit more practice and the chance to play the job in a raid setting.