If you have multiple popovers on the page, then it randomly selects a popover and opens it. The reason behind it is that all created popovers use the same id (ng-popover) and when you are selecting the popover to show, it is using the element id to select.
In effect, the first popover you click is correct, but after that, it stops working. I suggest refactoring to use class based selectors and a storing the title in a data attribute and selecting the correct popover based on the title.