Have run into an issue recently. I use subforms however when a user filled in a subform row they did not fill out some fields. When I tried to make these fields "Required" it reflected when trying to save a new record instead of when focused just on the subform row.

For example

In a module called Courses, we have a subform called Students.

Each course then has a list of students. For the subform a user must enter the "Student Status" when a student is starting the enrollment process.

The problem: You are unable to create a new course as the "Student Status" field is required. 

Solution: Set this field to be only required when edited the subform.