Can't destroy angular-strap popover

I'm creating popovers with angular-strap using the $popover service like this:

this.popover = $popover(this.element, {
            title: 'popover title',
            content: 'popover content',
            trigger: 'hover',
            container: 'body',
            html: true
          });

This renders correctly:

However, when I try to destroy the popover, it doesn't remove it completely because when I hover over the element, it shows this:

I've tried separately both of the following lines of code which produce the same empty popover result:

this.popover.destroy();

this.popover.$scope.$destroy();

What am I doing wrong?