If you look at a
cut away view of an EZ lube axle, you can see that the grease goes thru a port to the rear of the hub, then thru the inner bearing, then into a void area in the hub, then thru the outer bearing, and then out the front of the hub.
If the hub is full of grease, then the old grease will start coming out the front around the fitting after 10-15 pumps (as I remember). But it will take a half tube or more before new clean grease starts coming out.
If the person who did your previous greasing removed the hubs and hand packed, he probably did not fill the hub void area. Probably just packed the bearings themselves. That would mean you would not see grease come out the front until that void filled with new grease.
When pumping grease in the fitting, remember to pump slowly and keep the wheel turning continuously as you pump to help the grease go thru the inner bearing and prevent excess pressure on the inner seal.