Problem with tightening harness on Chicco KeyFit 30

[KatieGrace]

I am not sure how to fix this...my baby is 4 weeks old...under 11 lbs so he has the infant insert still in, shoulder pads, and head support. Straps are in the second slot and are slightly below his shoulders. I get him in the seat and get his straps on and get him buckled in then go to tighten the harness and the right strap is ALWAYS more loose than the left strap. I will loosen the straps, take him out and the straps are the same length. I will try to loosen the left strap only to see if that helps...nothing I do works. EVERY time I go to tighten the straps, the left one tightens right up and the right one is more loose. WHAT am I doing wrong? I will take him out again, make sure straps are even and try again...same thing. It's so frustrating!! Is there a trick or something to this? I've never had this issue before with any other seat. I want to love this seat, but I'm SO frustrated. Help!