Unless the expansion tank cap is defective, even though it is new, or you are overfilling the system, bleeding coolant indicates the system is overheating enough to reach the pressure release point for the cap. That could be because of a leak where the coolant got too low or a thermostat or waterpump problem. All of these should have caused the temp to run higher long enough to be noticed before a hose bursting.

I would fill it with water after replacing the hose, let it run until it has been at operating temp for 30 minutes and check for leaks or white smoke out the tailpipes before filling with coolant. It could also be the expansion tank leaking giving the appearance the leak is coming from the cap. I would get out my handy dandy auto stethoscope and put the probe on the water pump and listen for a growling noise. Look for indication coolant is leaking from the pump. Replacing the hose may be all you need to do but since you are losing coolant from the expansion tank I would check for a contributing problem causing overheating.

You never saw any indication of coolant on the ground after having driven at operating temp for 25 or so miles?

__________________
X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas