The integration with IFTTT will be discontinued in September 2024.
When you change a setting for a tado° product using IFTTT, your tado° switches to Manual Control. This happens because the tado° app records the change as a manual change on the device.
Note that IFTTT works via a cloud-to-cloud connection. So you always need a working internet connection to communicate with your tado° devices over IFTTT.