Just discovered that the following doesn’t work too well..
Mikrotik RB600A V4.0b4
Mikrotik R2N
802.11 b/g/n
WPA
Virtual AP with the same SSID as the main interface
The reason for the above security and Virtual AP interfaces is because this is a school and we want a secured network, and the virtual interface with the same security profile helps with irritating intel cards that like to “hop” around our APs. The Virtual convinces them to stay on the same unit, while satisfying their hopping desires. 
The issue I had however (Which is simply solved by disabling the virtual ap) is a logfile full of “wlan1: Data from unknown device , sent deauth”, and usually followed by “wlan2: Unicast key exchange timeout”.
The above may not be fully accurate, I forgot to take a screendump.
This occurred when there was a decent number of clients (more than 4, as I had one unit running fine with 4) trying to use the ap
Just thought I might post this incase someone else was chasing the unicast key exchange timout error like I was. 
I also tried V4.0b3 but it did the same thing.