@Pingouinos 

Thank you for the feedback. Can you check if this issue exists when you control the devices with Tapo APP directly under the local network (same wifi as the Tapo devices)?

The smart action is a cloud service, if there is any data-packet loss under local environment, it will affect the remote control (in your case, the smart action feature). 

You can try to ping the IP address of the Tapo switches and light bulb with a PC under local network, see if there is any Ping loss.