Thanks for your suggestion. I'll definitely go to the store tomorrow and buy frozen soybeans and see if I react.
Right now reaction is almost guaranteed with soybean oil. Soy lecithin also does, but quantity is also required. I can get away with little bit of soy lecithin. For example, my DIY liposomal vitamin can with soy lecithin broke me out because I was consuming large amounts of it.
I still don't know why it's happening and how to cure it.