P: How do I force Generator to generate assets?

Generator is the greatest thing I've discovered in Photoshop in a long time, and of course it continues my love hate relationship with Adobe product. I love it...when it works.

It seems very temperamental. Sometimes I just can't get it to generate assets. The Image Assets checkmark is checked and my file is all set up correctly, it just doesn't produce anything.

Sometimes changing layer comps triggers it to start working, sometimes I'll have to remove an extension in a layer name, then re add it, sometimes just reopening photoshop or the file itself gets it working.

Any tips on this? Is this a known issue? I'm actually dealing with a PSD right now that I can't get to generate assets no matter what I do, and I've quadruple confirmed that everything is set up correctly.

Thanks for any input.