I had this same issue, using Beaver Builder with the Astra theme. In my form, when a single column came after several rows with multiple columns, the div for the single column would cover them up, making them unresponsive to clicks.
Turning “Base and Form Theme Styling” back on as suggested and adding new CSS to style the submit button worked as a fix for me, because thankfully the rest of the default styles were acceptable.
Thanks for the fix. I do have a question though: If Form Theme Styling is required for forms with a mix of column sixes, what’s the point of having a “Base Styling Only” option? I like WPForms and will likely use it for other client website in the future, but may need the option use base styling only.
Cheers, Sarah