Airbag light question

Does anyone know why my airbag light comes or what to do, I noticed this after I swapped bench seats out but it only comes on in mornings when it’s cold outside. Took it to dealer and all they said was incompatible seat but the seat was same thing as what I took out. After I noticed it in my truck I started noticing it does the same exact thing in my 2012 Corolla and I haven’t changed anything on it and had it since new. If I shut the vehicle off then start back up it usually goes out on both vehicles but does anyone know why this happens especially only when it’s like below 30 outside