When I start my Yukon every morning, it starts to leak coolant then stops. on 1997 GMC Yukon

When I start my Yukon after it has been setting overnight, it starts leaking coolant from the heater control valve area. After it warms up, the leak stops. This has been going on for a while. I've had the heater control valve and adjacent hoses replaced but it still does this. Anyone know what's going on?

Asked by for the 1997 GMC Yukon