[This paper is part of the "Focused Collection on Instructional Labs: Improving Traditions and New Directions."] Recent studies provide evidence that social constructivist pedagogical methods such as active learning, interactive engagement, and inquiry-based learning, while pedagogically more effective, can enable inequities in the classroom. By conducting a quantitative empirical examination of gender-inequitable group dynamics in two inquiry-based physics labs, we extend results of previous work. Using a survey on group work preferences and video recordings of lab sessions, we find similar patterns of gendered role taking noted in prior studies. These results are not reducible to differences in students' preferences. We find that an intervention which employed partner agreement forms, with the goal of reducing inequities, had a positive impact on students' engagement with equipment during a first-semester lab course. Our work will inform implementation of more effective interventions in the future and emphasizes challenges faced by instructors who are dedicated to both research-based pedagogical practices and efforts to promote diversity, equity, and inclusion in their classrooms.