My 6 month old puppy is perfectly fine off the lead, perfect recall everything. Until she sees a jogger she's off. Ignoring everything, our voices, the whistle everything! She'll chase them barking and growling. I'm sure it's scary for them! So we've had to keep her on a lead as soon as we see one. We've tried to get her use to them by having one of our family members jog past and she reacts the same. Any advice please?