The collaborative nature of introductory college science labs means that labs can play a major role in boosting students' interest in experimental science when they work together in small groups. However, collaboration in lab courses is not always positive for all students. We report on a study that documented how women in mixed-gender groups in a remote physics lab course described being ignored, talked over, or not being taken seriously in online physics labs. We also investigate the impact of providing detailed grading rubrics on the engagement of different types of mixed-gender groups and the influence of group roles on productive interactions between students in the class. Based on our findings, we suggest that providing clear and explicit grading criteria with frequent and timely grades, as well as integrating group roles into learning activities, may provide effective and complementary ways to make the introductory lab a more equitable and inclusive learning environment.