[CentOS] 7.7.1908, interface bonding, and default route

Hi!

I just upgraded a machine to 7.7.1908 and the default route is not being
set on boot. This particular server has a bonded interface, and the
corresponding configuration for the master is (
/etc/sysconfig/network-scripts/ifcfg-bond0):

  TYPE=Bond
  BOOTPROTO=none
  DEFROUTE=yes
  IPV4_FAILURE_FATAL=yes
  NAME=bond0
  DEVICE=bond0
  ONBOOT=yes
  IPADDR=10.3.20.131
  PREFIX=24
  GATEWAY=10.3.20.1
  DNS1=10.3.2.8
  BONDING_MASTER=yes
  BONDING_OPTS="mode=802.3ad xmit_hash_policy=layer2 miimon=100"

The slaves (two of them) are configured like

  TYPE=Ethernet
  BOOTPROTO=none
  NAME=bond0-slave0
  DEVICE=em3
  ONBOOT=yes
  MASTER=bond0
  SLAVE=yes

After booting, the routing table is

  10.3.20.0/24 dev bond0 proto kernel scope link src 10.3.20.131 metric 300

with no default route configured (manually adding it will work, of course.)

This machine worked perfectly before, and it did during previous upgrades
and reboots. Has anyone ever had this problem before?

Thanks,
Carlos.