Reoccurring Antifreeze Leak with Water Pump after 3 Repairs (so far)

Hello Good People, I'm wondering if anyone has any experience with an issue in regards to reoccurring leaking water pump or connected parts. After I bought my 2005 Prius I took it to a Toyota dealer for an evaluation, they recommended replacing some air filters and replacing a leaking water pump. They brought me back and showed me the crusty remains of fluid on one of the joints on the assembly.(I never saw any fluid under the car) I had the work done and in a week I was getting plate size leaks under the car; took it in and they gladly replaced the unit, in about another week, I was getting a steady drip that seemed to be growing in size every day, took it in this morning; I was told, that the entry point hadn't been properly cleaned and crusty old fluid was preventing a perfect seal. They cleaned the area, so that it's flush. Got home this afternoon and within 3 hours I have 2 fluid spots in 2 different location; cleaned the pan waited another 3 hours ...and sure enough I have another 2 spots in same area as previous. There are 2 places leaking, small but there. Could it be residue fluid dripping from the unit? I know time will tell, but I have never had this kind of issue with any mechanic before. So, is there a problem with water pumps leaking for Prius 2005? Is this a thing? Previous to replacing water pump, the vehicle was not leaking in a way that I saw fluid on the ground (or pan) and now it is, so I know it's possible for the car to be leak free. This seems so strange to me. Any advice about what may be happening?

 

Thanks; yesterday they told me the team leader was working on it, but obviously didn't do a pressure check on the system after the repair was complete to make sure. Incredible. That's a good idea in having them keep it, so they can watch it for themselves. Thanks, I wouldn't have thought of that. I appreciate the suggestion.