What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
I am not reproduce the same issue that you're having. It is working properly on my side.
However if you are still having that issue you can add the CSS code below from designer:
margin-bottom: 0 !important;
padding-bottom: 0 !important;
As an alternatively, You can decrease your line spacing of your form as you see below.
If it doesn't work please let us know. We can solve your issue with different way.