Electrolysis damage to my radiator after 5,000 miles?

[Nodnarb76]

I would like to get everyone's opinion on something.
When I did my LS swap 3 years ago, I bought a radiator/fan combo from Entropy radiator. about a year and 7000 miles later it started leaking. I sent it back to them and they replaced it under warranty.

Last month it started leaking again from what looks like the same spot. I sent it back in to them. After two weeks I call to check up on it and I am told they won't cover it under warranty because they determined it was Electrolysis damage that caused it to leak. They offered to sell me a new radiator for 1/2 price. After doing some research It looks like Electrolysis happens on older cars/cooling systems when the coolant is old, and the engine isn't properly grounded.

I only have about 5000 miles on the radiator since they sent it to me last time, and every time I have had the radiator out, I use brand new pre mixed AC Delco coolant. I have the battery grounded to the frame, block, and radiator support. and also have the block grounded to the frame and firewall on the other side.

Could I have an Electrolysis problem with only 5000 miles, new OEM coolant, and 5 grounds?