File /etc/systemd/network/eth0.network as provided by recent root filesystem archives states
$this->bbcode_second_pass_code('', '
[Network]
DHCP=yes
')but "yes" isn't an accepted value here according to man 5 systemd.network.
I couldn't see any malfunction due to this yet. Rather, it seems to behave much as if "both" had been set. But maybe it would make some sense to change this to "both" in upcoming versions nevertheless?