I'm using the Lightbox trigger feature with views and the rel attribute, including the group name, is being generated as follows:

lightmodal[lightbox-popup-{$this->view->name}|width:512px;height:512px]

Line 122 of lightbox2_handler_field_lightbox2.inc is:

$group_name = ($this->options['rel_group'] ? 'lightbox-popup-{$this->view->name}' : '');

To fix the problem, I changed the line to:

$group_name = ($this->options['rel_group'] ? 'lightbox-popup-' . $this->view->name : '');

In the view ("Competition Winners") this now reads as I imagine it's supposed to:

lightmodal[lightbox-popup-competition_winners|width:512px;height:512px]