Refresh rate of the clock in the title

Hello everyone,
I activated the clock in the title of the habpanle pages, but it refreshes once in an hour. The time format is HH:mm so this refresh rate is unuseful . It should be more frequent to read correctly the time. My setup is:
OH: 3.0.1-2 migrated from 2.5
HW: Raspberry pi 3
OS: raspbian stretch

Does anyone else is experiencing the same problem?