Why doesn't my boomerang / slow-mo use the template?

Starting with the iPad app version 1.1.0, boomerangs and slow-mos will use the first 1-photo template assigned to the event. Starting with version 1.3.0, there is a setting to turn this off if it's not what you want.

If there is no 1-photo template (a template that has exactly one photo area) assigned to the event, then your boomerangs and slow-mos will not have any template applied to them.