@TUMAS 

May I know the model of your Kasa smart device? You could try some basic troubleshooting if the runtime is not correct.

Please confirm the Kasa app to date and kasa device firmware are both up-to- date
Try a factory reset on smart device and resintall it in the APP :
How to reset TP-Link Kasa smart switch and plug

There isn't  notification for schedule or timer in kasa app yet, while there is a way to see if the schedule has started. Before the schedule rule take effects there is an event below the smart device on Kasa APP mainpage, if that event has gone and goes to next event, that means it has take affected.