If I have a reference track in cubase and want it to go directly to out bypassing inserts on master bus how can I do that ?
I tried creating a pre-bus / group bus. But cubase doesn’t allow effect returns and other busses to be routed to this buss
Now if once again, we only knew what software you are using… 
Cubase 8 (full, not artist or studio or elements)
Most probably you have a feedback loop going on. Otherwise you should indeed be able to route everything but your reference track to a sub main bus.