First available all going to one printer?

[twlum 3]

I have 4 UM3 and 3 of them are running the exact same configuration of .4 nozzles, Generic PLA in Extruder 1 and Breakaway in Extruder 2. I have my class learn to use the printers and CAD software by creating and printing a key fob. When they are finished designing it, they open Cura and I have showed them how to slice it and print it to a networked printer. They choose "Print over network" and then "Automatic". When I launch Cura, it shows the queue and the jobs say waiting for "First available" but only one (sometimes 2) printers are printing while the third sits idle. I open up Manage in browser and it shows they are all waiting for one specific printer. What is going on here and what can I change to make sure the load of printing is distributed evenly? 

To investigate further, I went and sliced a fob and chose "First available" and it went right to the idle printer and started warming up. Weird behavior...