Why can a smart scene be executed only once?

The automatic scene shown in the following figure is used as an example. The edge trigger is used to determine the air quality. If the air quality in the area where you reside is always polluted or good, Tuya Smart cannot reset the triggering point of the edge trigger. As a result, the automatic scene does not take effect after being executed once. It is triggered again only when the air quality changes to excellent and then to good or polluted. You are not advised to enable an air purifier through automatic control.