New iTunes connect interface error “You must choose a build”

Question

When trying to submit my new app to the app store, I noticed Apple has changed its website interface: after updating metadata and keywords and hitting \"submit for review\" I go

Answer 1

Just visiting the Prerelease tab and then navigating back to the Versions tab for some reason then displayed the "+" symbol on the Build section.

I waited ~45 minutes to see if it would happen automatically, but that's what worked for me.