Newer adaptors with 4 holes are OK. The ones with ten holes are not.

Baby Jogger Recalls 30,000 Stroller To Car Seat Adaptors

It’s very convenient to take your child’s car seat and mount it directly on a stroller…unless the adaptor that lets you do so is faulty. There have been 47 reports that adaptors for Baby Jogger strollers have failed: specifically, the part that connects the bars that support the car seat to the stroller frame comes loose, and the car seat hits the floor. [More]