systemd fails to set up timesyncd.service with the NTP server provided by DHCP.
I just tested this on systemd version 216-3 and 217-3 on Arch x86_64
I was referred here by the Arch Linux folks
Installing NetworkManager does not fix this issue - should a separate bug be filed here as well?
Steps to reproduce:
Pristine base install, rebooted # Use ip link to retrieve interface name
dhcpcd -T enps0s25 # Observe ntp_servers stanza in response
systemctl start dhcpcd@enps0s25
timedatectl set-ntp true # Start NTP client
timedatectl # Confirm NTP is enabled and in sync
journalctl -f # Observe NTP on default time*.google.com
Well, it does work with networkd's dhcp implementation.
However, there's no standardized way how a generic dhcp implementation like dhcpcd (which you appear to be using) could inform the rest of the system about the NTP servers it learnt.