Is team performance in project based PBL better if all team members have the same work ethic?

All Engineering Educations at Aalborg University uses Problem Based Learning as learning method on each semester where the students work in groups of 5-7 members on a 15 ECTS semester project supported by courses.
Groups with good communication and collaboration has a higher potential for peer learning and a successful sharing of knowledge than groups struggling to communicate and collaborate. A study in 2016 showed that the most well organized groups worked full time on the project at the University but also worked a lot on the project at home. Other groups preferred to do most project work at home and only meet at University for courses and a couple of meetings a week to discuss the progress of their project and assign new tasks. The well-organized groups used peer learning more than the other groups and received better marks.
These results was presented for students studying Computer Science in the beginning of their first semester 2017. In October, new groups was formed and the students used the knowledge to form homogeneous groups where either all members wanted to work full time at the University or all members preferred to do most project work at home.
This paper investigates if these groups perform better, have fewer conflicts, and dropouts than another cohort with less homogeneous groups, by analyzing and comparing written process analysis from each group, personal learning portfolios from each student and student dropouts.
The first findings shows higher retention, less conflicts and more peer learning in homogeneous groups.