Recently i had a similar issue where the controller would hang it self and lagged way too much on random occassions,even after plugging
my own pc to the network the same thing happened,reloaded system same results,connecting it directly no issues.Long story short a pc(out of 10) from the network lagged the fiery..
No idead how,if you disconnected that pc all was well,connect it again and the fiery lagged as hell.