[xxxx] systemd[1]: apt-daily.timer: Adding [...] random time.

Hi

What's going on ? (after 16.04 update)
With dmesg command I can see lots of
systemd[1]: apt-daily.timer: Adding ...
systemd[1]: apt-daily.timer: Adding ...

12:26:09 2016] systemd[1]: apt-daily.timer: Adding 8h 28min 47.193961s random time.
12:26:09 2016] systemd[1]: apt-daily.timer: Adding 1h 57min 31.990092s random time.
12:26:10 2016] systemd[1]: apt-daily.timer: Adding 8h 16min 15.319923s random time.
12:26:10 2016] systemd[1]: apt-daily.timer: Adding 4h 52min 31.257086s random time.
12:27:08 2016] systemd[1]: apt-daily.timer: Adding 5h 17min 44.607579s random time.
12:27:08 2016] systemd[1]: apt-daily.timer: Adding 7h 53min 48.623782s random time.
12:28:51 2016] systemd[1]: apt-daily.timer: Adding 6h 51min 2.576228s random time.
12:28:52 2016] systemd[1]: apt-daily.timer: Adding 9h 14min 10.164084s random time.
12:28:52 2016] systemd[1]: apt-daily.timer: Adding 6h 50min 2.272500s random time.
12:28:52 2016] systemd[1]: apt-daily.timer: Adding 39min 6.687065s random time.
12:28:52 2016] systemd[1]: apt-daily.timer: Adding 7h 1min 59.797804s random time.

find same question on the net, without any answer... :-(

Is this an expected behavior ?

Thanks.