So by the sounds of it, it could be one of many things!
She does it on lead and off, and starts as soon as she notices people walking towards us, (I can be walking on the path with the stranger walking towards me, and Paige will be in the middle of the adjacent field when she will notice someone approaching me, or hubby, and will run over barking)
I do tell her off and tell her to be quiet but it doesn't make any difference.
I used a clicker to originally train her to recall so I know that does have a positive result with her.
It is obviously going to be a lot of trial and error.
Thanks.