I previously owned an 03 Journey DL 34H. I had to repair that hose on my first outing when the coach was brand new. I'm surprised that yours took this long to leak. It's a really bad design and Winnebago used the wrong glue on the connections. The dealer and the factory both tried to repair and both failed.
The third time I did the repair. I replaced the DWV fittings with pressure fittings (they have much more surface area) where the flex is connected. I used the proper primer and PVC glue that is approved for flex pipe. Also, I installed 3 stainless sheet metal screws through the fitting into, but not completely penetrating, the hose.
After that I had no further problems. I traded it in 2012.
2019 Phaeton 37BH