Unbalanced transmit load with bond mode 5 (balance-tlb) on rhel-6

Issue

Transmitted traffic does not appear to be well balanced across all slaves in some rhel-6 releases.
There are rhel-6 releases which do the balancing of outgoing traffic well across all the bond slaves and some which do not.

Four slaves bond instance with not well balanced outgoing traffic :

Bond: bond0 (active slave: eth1)
 Total TX packets: 4398303
  eth1: (20.6800%) 909741
  eth2: (18.0200%) 792644
  eth3: (35.2900%) 1552353
  eth4: (26.0000%) 1143565

Four slaves bond instance with well balanced outgoing traffic :

Bond: bond0 (active slave: eth1)
 Total TX packets: 8887258
  eth1: (24.1800%) 2149040
  eth2: (25.5900%) 2274593
  eth3: (26.0300%) 2314223
  eth4: (24.1800%) 2149402

Well balancing rhel-6 releases:

• rhel-6.4 (kernel-2.6.32-358.*.el6)
• rhel-6.5 (kernel-2.6.32-431.*.el6)
• rhel-6.6 (kernel-2.6.32-504.*.el6)

Not well balancing rhel-6 releases:

• rhel-6.7 (kernel-2.6.32-573.*.el6)
• rhel-6.8 (kernel-2.6.32-642.*.el6)
• rhel-6.9 (kernel-2.6.32-696.*.el6)