Problem with LightBox Popup Form?

This WAS my lead-capture model:
Landing Page captures name/email.
On Submit, 2nd Landing Page Formcaptures full contact info.

Now, I'm suing this model:
Landing Page captures name/email.
On Submit, Lightbox Popup Form captures full contact info.

Now, I'm seeing more frequent issues where leads aren't completing the 2nd Form. I know there's a very slight delay between the Submit and the Lightbox Popup.

Any insight into this issue is appreciated. I'm thinking of creating a B-test that goes back to the original model to see if I get better results that way.