Current time running behind on Rasbian Buster SD image on pI 4

I installed deconz on my Pi4 using the SD image:

It seems that the time is always lagging behind for about 15-30s, even after a fresh restart. This causes weird issues with “Last Updated” times in my 3rd party app for frequently updating sensors.

I noticed these steps, but it sounds something that should be configured by default on a Pi?

Maybe a control device like a tablet in the local network accesses the Phoscon app which has not set an exact time?

Not sure what you mean? On the Pi itself (ssh) I see that the current time is wrong, and the debug logs confirm that. How would that be affected by a control device?

The time of the Phoscon gateway is also generate via the device/ browser you access the Phoscon App, but maybe this in independent from the Pi system clock.