The reason why lemon flavored soda has a soapy taste may be related to its production process and ingredients. Soda is a drink that is made using a mixture of ingredients such as food flavorings and sodium bicarbonate. In some of the production processes, soap-like flavors may be used, which can lead to the appearance of a soapy taste. In addition, the weak alkalinity of the soda itself may have an effect on the flavor.

Overall, different production processes and ingredients may make each soda taste slightly different, including some that may have a soapy flavor. If you have questions about the flavor of a particular soda, it is recommended that you consult the manufacturer of the product or a professional for more detailed information.