Maybe i did not describe my observation clearly enough and chose the wrong section as it is not a problem of automations but seems to be more a generic "bug" or intended "misbehaviour" ....
I DO know how to configure automations. I was implementing this MQTT-timesync method as my ESP32 based HV-battery controller can not use an ntp client nor an sntp client as both of them cause blocking timeouts in the espidf environment.
Those 170 seconds are the offset of the REAL time (which is correctly displayed and used in HA) and the WRONG raw value. I hope the attached screenshot describes ?!