Not sure where your training your bird but sometimes they will take the other route, especially if they percieve it to be easier or I think sometimes they do it just to be defiant
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When I had to retrain Ollie to step up because he got scared of me he frequently tried to avoid stepping up by walking round even though he knew what I wanted him to do, he was just scared I was going to give him more meds.
I found practicing moving targets very helpful (but if your bird isn't used to following a target that moves you need to practice it first), basicly if he walked around my hand to touch the stick I would move it back to the other side of my hand before he could touch it to get his treat so he would walk back round. Eventually he realised it was easier just to jump on my hand than repeatedly walk round and round but he still had a choice.
Another way is to move your training location, for instance to a perch which makes it impossible for the bird to walk round, it will either step up or it wont in order to reach the stick. The risk here is if it decides it doesn't want to step up in order to reach the target your also lowering your successful command rate which may teach the bird more that is doesn't have to respond (it doesn't of course but no need to encourage that idea) for that reason I would go with the moving target idea if the bird will still successfully target most of the time.
