Raypak

Has anyone else noticed a lot of defective heat exchangers. The number 2 tube leaks where it is machines or soldered into the Stainless Steel plate. I have 3 that have failed in the same spot. One lasted 3 months, the 2nd lasted 30 minutes, the third leaked after only 5 minutes!
Here is my story:
My customer , who lives a few doors down from President O’Bamas house in Hyde Park, Chicago, bought a 2nd new Raypak/Ruud gas pool heater ( M266A) around Christmas 2021. I installed it, and after just 3 months, it was leaking at the heat exchanger.
At first, I thought the pool chemistry must be way off, but soon learned it was fine.
I ordered a new heat exchange tube bundle from Horizon Spa parts, a big and reputable pool and spa parts distributed whom I have used since 2008. I installed the replacement heat exchanger, tested the pool chemistry again, and turned it on. Within a few minutes, I could smell something was not right. I was hoping it was just dust and stuff from repair job was burning and that it would soon be OK. However, after 30 minutes, I took my Ferret camera and took a video looking up from the bottom near the burner. Major bummer; the brand new exchanger was leaking at the #2 tube joint.
I ordered a 2nd new heat exchanger and they delivered it. This time, I assembled the exchanger, replaced the bypass thermistat, inspected that everything was absolutely clean, and gave it a pressure test of 20 pounds full of water with no leaks.
The next day, I went back to Obamaville, and installed the 2nd new exchanger into the nearly new heater and turned it on. No leaks with only water pumping through. However, after I turned on the gas heat and the flame started heating the tubes, it started leaking within 5 minutes.
I sent both heat exchangers back to Horizon, and asked for a refund. I then replaced the whole heater with a Jandy heater, and it has been working fine.
Horizon is blaming water chemistry and not refunding my money. The customer is out several thousand now, and I have wasted $1600 in time and labor. Their warrentee is worthless in this case, as I am not an “ Authorized Raypack installer”, so all I can do is warn everyone, especially Raypak, that they most likely have hundreds of defective heat exchangers. I think it’s the stainless steel plate, or the machine needing adjustment, not bad copper, that is causing them to hold water when cold, then leak when hot.
If they are reputable, they will correct this defect ASAP, and send my customer a whole new heater.
Customer is willing to pay me for all this wasted time, and I’m lucky for that. I wonder, however, If they will have their Lawyer look into it, or just take the loss of $2300 for Heater, plus $800 for worthless heat exchanger, and $1600 labor, that’s $4700, plus the cost of another new heater. Most likely, a Different brand.