We had a black tank issue for almost a year when we got our 2017 Alpine. It would not dump you had to pull the valve handle 7 to 10 times waiting about 3-5 minutes between each dump. I was in and out of camping world every other month until we finally laid the law down to them. Our service Tech told them the problem over and over this time they listened to him. the black tank wasn't getting AIR when they installed the roof air vent they left a piece of plastic from the tank so when we pulled the black tank dump the piece of plastic from the tank would close shutting off the air flow and stopping the water to discharge from the black tank.
