One problem related to air bag on-off switch has been reported for the 2021 Hyundai Sonata. The most recently reported issues are listed below.
We lease a 2021 Sonata sel equipped with air bag system featuring an OCS in the right front seat. The purpose of the OCS is to disable right passenger seat front air bag when it detects ta child restraint system or small child in the right front seat. Right front air bag is disabled to prevent injuries to a child from a right front air bag inflation during a crash. My wife is about 4'10" tall and weighs 135#. When seated in passenger seat, she requires a cushion to raise her so she can see over dashboard and out side window. Our Sonata is equipped with manual passenger seat that is raised to highest position. Problem is that when she uses cushion, the OCS light stays on indicating that air bags are deactivated and would not deploy in an accident which could cause an extreme safety hazard to my wife. We took car to dealer service center twice, and we called Hyundai USA customer service - both said nothing could be done. Small adults like my wife should be able to bypass the OCS using a shunt or bypass switch. We feed this is a serious safety hazard. Earlier Sonata models were recalled for this issue.