High squat mobility, poor control. This is more common in females, but also in males who've played sports that demand extra mobility as a kid, or who have a lot of congenital joint laxity.
For these people, they need to focus on trying to control the movement more, which means slowing down and thinking about positioning and trying not to bounce through the movement.
A forward lean on lunges increases the recruitment of the glutes and hamstrings. The dumbbells should be on the side of the front foot in the bottom position.