LO keeps head turned 90 degrees when upright?

LO has always turned her head to the left, but lately she keeps it turned 90 degrees whenever she's being held upright. She keeps her head centered when she's on her back and during tummy time, as well as when she's sitting and standing. She can look around 180 degrees without any problems.

She also favors her left hand for chewing/sucking/grasping. She doesn't do anything with her right hand. Should I be worried? My first thought was torticollis, but she does a 90 degree turn, not a tilt, and it's only when she's being held upright.