Wrong config file after bond re-configuration

[xenolog]

After try to reconfigure bond from 802.3ad to active-backup mode
result config file contains unrequired options for LACP bond:

config file before re-configuration:

root@ubuntu:~# cat /etc/network/interfaces.d/ifcfg-bond0
auto bond0
iface bond0 inet static
address 192.168.168.3/24
bond-slaves eth1 eth2
bond-mode 802.3ad
bond-miimon 50
bond-lacp-rate fast
bond-xmit-hash-policy layer2+3
post-up sleep 45

config file after re-configuration:

root@ubuntu:~# cat /etc/network/interfaces.d/ifcfg-bond0
auto bond0
iface bond0 inet static
address 192.168.168.3/24
bond-slaves eth1 eth2
bond-mode active-backup
bond-miimon 50
bond-lacp-rate fast
bond-xmit-hash-policy layer2+3
post-up sleep 15

should be:

root@ubuntu:~# cat  /etc/network/interfaces.d/ifcfg-bond0
auto bond0
iface bond0 inet static
address 192.168.168.3/24
bond-slaves eth1 eth2
bond-mode active-backup
bond-miimon 50
post-up sleep 15