Q: Keynote doesn't do transition effects between slides

I am using Keynote 6.61 and El Capitan. I've set all my 10 slides to transition using Dissolve at 1.25 second intervals. My transitions are "on click." The slides indicate a preset transition. Previewing the effect works. Slide objects animate properly.

When I play the slide show, however, there's no transition effect; the new slide just appears, replacing the old one. This OS and software build is pretty new, only a few months' old and this is the first Keynote presentation I've made since installing the software. Any suggestions on configuring it to work?