2.4.3 Focus order
Do not design content in a way that is known to cause seizures.

About

Site visitors use the tab key to move between the fields in a form. In order to enable the screen reader and keyboard users to move between form fields (and links), the logical order of the form for tabbing should be determined. The order in which form fields receive focus is called the tab order. By default, the tab key will start at the top and works its way down the page. Failing to provide a logical tab order is highly confusing and makes the task of navigation very difficult.

Example:

Before Rectification

image with non-focus Tab order

After Rectification

image with a focus Tab order