Doing some drawings of the different hosts, vmkernel and service console I have noticed that 2 out of the 6 server hosts got misconfigured for the teaming nics.
Servers 3 and 4 were using the same active nic for vmotion and management traffic.
I thought, yeah great, finaly! However my coworker said that the traffic that caused the issue was coming from server 1 and 2.
How can it be? I'm puzzled here 
I'll trigger some vmotion tomorrow morning early to see if there are any improvements and will report here.
As always, any thoughts are welcome. 