Surely it has to be running at a lower pressure than the compressor or you would get flow reversal as in a surge, therefore would it effect the compressor? Wasn't the problem they had to do with the change of direction in the nozzle, though they had cured that before it got canned.
I take it we are talking Pegasus, that was the core engine based on the Orpheus out of the Gnat with a bypass fan nailed on the front, the fan feeding the forward nozzles and the hot end the aft ones.