Variables within templates - is there a trick?

Hello - I'm working with a template file of around fifty slides. There are some common variables across all the pages, an example being 'Title'. When I import all the slides from the template file, then all of the variables are present, and the triggers look good.  If I chose to import a few of the slides, then the 'Title' variable is not brought in (or at least, it seems intermittent), so the triggers on those slides that rely on the Title variable are all broken, and are not recreated if I then manually add back the missing Title variable using the 'x' button.

I'm guessing there's some kind of trick or workaround to ensuring that the variables referenced in the template are preserved no matter which combination of slides are brought in, but I can't figure it out. With fifty slides there are an impossibly large number of combinations to experiment with to find what causes variables to be either included or not. In my example, the Title variable is referenced in a text box on each page (%Title%).

Any ideas? Anybody else had to deal with this?