indoor coil corrosion and leaks

This is old news but don’t remember seeing much on here about it.
Lots of bad indoor coils in the last 10 years…

Here is a “study” done by Carrier on the problem:

I had a recent client decide to get an HVAC guy to check all three 8yr old systems for refrigerant leaks before buying the house (he had just experienced bad coils on the house he sold). It ended up needing two indoor Carrier coils replaced. I heard it cost the seller $3000