Raspbian receives DHCP 20 seconds, how to fix?

Question

linux

RaspberryPi 2 B+ with the latest Raspbian on board re-obtains IP via DHCP for 20 seconds during reboot, which renders many Startup scripts tied to the network unusable.
Apparently, the hero of the occasion is the newly introduced dhcpcd.
Who faced this, how can this be fixed?

Jul 27 18:25:54 RPI dhcpcd[1802]: all: IPv6 kernel autoconf disabled
Jul 27 18:25:54 RPI dhcpcd[1802]: eth0: IPv6 kernel autoconf disabled
Jul 27 18:25:54 RPI dhcpcd[1802]: eth0: adding address fe80::ba27:ebff:fe5e:a873
Jul 27 18:25:54 RPI dhcpcd[1802]: if_addaddress6: Operation not supported
Jul 27 18:25:54 RPI dhcpcd[1802]: DUID 00:01:00:01:1c:dd:60:5f:b8:27:eb:5e:a8:73
Jul 27 18:25:54 RPI dhcpcd[1802]: eth0: IAID eb:5e:a8:73
Jul 27 18:25:54 RPI dhcpcd[1802]: eth0: rebinding lease of 10.1.2.25
Jul 27 18:25:59 RPI dhcpcd[1802]: eth0: probing for an IPv4LL address
Jul 27 18:26:00 RPI dhcpcd[1802]: eth0: DHCP lease expired
Jul 27 18:26:00 RPI dhcpcd[1802]: eth0: soliciting a DHCP lease
Jul 27 18:26:05 RPI dhcpcd[1802]: eth0: using IPv4LL address 169.254.145.138
Jul 27 18:26:05 RPI dhcpcd[1802]: eth0: adding route to 169.254.0.0/16
Jul 27 18:26:05 RPI dhcpcd[1802]: forked to background, child pid 2551
Jul 27 18:26:27 RPI dhcpcd[2551]: eth0: offered 10.1.2.25 from 10.1.2.1
Jul 27 18:26:32 RPI dhcpcd[2551]: eth0: leased 10.1.2.25 for 172800 seconds
Jul 27 18:26:32 RPI dhcpcd[2551]: eth0: adding route to 10.1.2.0/24
Jul 27 18:26:32 RPI dhcpcd[2551]: eth0: adding default route via 10.1.2.1
Jul 27 18:26:32 RPI dhcpcd[2551]: eth0: deleting route to 169.254.0.0/16

Answer 1

As one of the search directions:
What is RaspberryPi connected to? How smart is the switch?
If it has a SPANNING-TREE protocol (builds a network tree) - disable it .

Answer 2

Show your dhcpcd.conf if possible.
As far as I could swang, you most likely don't have the "noipv4ll" parameter in your config, and the daemon sets up Link-Local on the interface first.