Issues enabling bond with non-zero `updelay` on RHEL 7.4 and system repeatedly logs "bond: link status up for interface, enabling it in ms" and bond slave MII status is DOWN

Issue

• Starting a bonded network with a non-zero updelay configuration neither forms the bond interface properly, nor fails over if their primary interface becomes unresponsive.

• RHEL 7.4 system repeatedly logs "bond: link status up for interface, enabling it in ms" and bonding slave MII status is DOWN

• System repeatedly logs the same "link status up" message:

  Aug 17 14:21:00 localhost kernel: bond0: link status up for interface eth6, enabling it in 2000 ms
  Aug 17 14:21:00 localhost kernel: bond1: link status up for interface eth2, enabling it in 2000 ms
  Aug 17 14:21:00 localhost kernel: bond2: link status up for interface eth3, enabling it in 2000 ms
  Aug 17 14:21:00 localhost kernel: bond0: link status up for interface eth6, enabling it in 2000 ms
  Aug 17 14:21:00 localhost kernel: bond1: link status up for interface eth2, enabling it in 2000 ms
  Aug 17 14:21:00 localhost kernel: bond2: link status up for interface eth3, enabling it in 2000 ms
  Aug 17 14:21:00 localhost kernel: bond0: link status up for interface eth6, enabling it in 2000 ms
  Aug 17 14:21:01 localhost kernel: bond1: link status up for interface eth2, enabling it in 2000 ms
  Aug 17 14:21:01 localhost kernel: bond2: link status up for interface eth3, enabling it in 2000 ms
  Aug 17 14:21:01 localhost kernel: bond0: link status up for interface eth6, enabling it in 2000 ms
  Aug 17 14:21:01 localhost kernel: bond1: link status up for interface eth2, enabling it in 2000 ms
  Aug 17 14:21:01 localhost kernel: bond2: link status up for interface eth3, enabling it in 2000 ms
  Aug 17 14:21:01 localhost kernel: bond0: link status up for interface eth6, enabling it in 2000 ms
  

• Additionally, the MII Status is always shown as down for these interfaces:

  $ cat /proc/net/bonding/bond0
  Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)
  
  Bonding Mode: fault-tolerance (active-backup)
  Primary Slave: eth4 (primary_reselect always)
  Currently Active Slave: eth4
  MII Status: up
  MII Polling Interval (ms): 100
  Up Delay (ms): 2000
  Down Delay (ms): 0
  
  Slave Interface: eth4
  MII Status: up
  Speed: 10000 Mbps
  Duplex: full
  Link Failure Count: 0
  Permanent HW addr: 10:15:a4:d8:c2:1c
  Slave queue ID: 0
  
  Slave Interface: eth6
  MII Status: down
  Speed: 10000 Mbps
  Duplex: full
  Link Failure Count: 0
  Permanent HW addr: 10:15:a4:d8:c1:e0
  Slave queue ID: 0
  

• The bug doesn't trigger 100% reliably, but can be provoked by removing and re-adding interfaces to the bond via sysfs.