Is GE building engines out of chinese pot metal these days? How could the engineers possibly have missed this?
It isn't the single metal, it's the plural of metals and an electolysis link between them. Things like coupling nuts, multiple shaft materials oils, etc. in a small compartment. The rate of corrosion is highly subjective. the fix is typically protect the metal (coating) and/or change the material.
I suspect that there are quite a few other examples in the literature.