Steps to reproduce:
- Setup a Liferay bundle from a version where Drag and Drop was not implemented.
- Go to Content > Forms
- Add a Form
- Add 5 fields in 3 columns following the layout: 1 - 3 - 1
- Save form
- Upgrade Bundle to Master
- Go to Content, Forms and open the form you created in step 3
Although you can no longer add more than a field to one column, you still can edit the form and it should be visually ok.
The column with three fields looks messy, making it impossible to edit the fields.