Is your toddler seat loose? I never noticed it until yesterday when my husband pointed it out, but when the toddler seat (which is what we use with our 8 month old LO) is connected it isn't that secure. If you pull straight up it stays latched securely. However, if you pull it at an angle either backward or forward it unlatches and becomes loose. This appears to be a safety concern and I'm not sure if it is just my stroller/seat or if this is just how they are designed. We are worried about this as he becomes bigger and more active if he's rocking and moving around in the seat.
Of course I purchased it last year during the free-ride event and discovered the problem 2 days after the one year warranty expires. I'm pursuing warranty issues through Am Ex because they extend by one year, so we will see what happens. I really like the stroller and was hoping to use it as a double one day, but now I don't know if I should get something else instead.