It is true that only people with certain genes can perceive this.The aroma and flavor compound S-Linalool, a naturally occurring chemical in scented plants, is also a major component of the oils found in coriander. More than 60% of perfumed cleaning agents and hygiene products contain linalool. In addition to that, pest professionals use it in the preparation of insecticides. Some mosquito repellent products also make use of linalool. This could be one reason why some people associate the soapy taste to coriander.
Coriander also has some aldehydes that are found in soaps, detergents, and lotions as well as the bug family of insects. Soap has a taste of sodium fluoride. These aldehydes, mainly (E)-2-alkenals and n-aldehydes, are responsible for the soapy taste in coriander.
Once again proof that I'm a perceptive person