shift linkage tohatsu 9.8

I installed two 9.8 xls three months ago on my 36 catamaran. Just last week one engine failed to shift into forward. it turns out the coupler that holds the shift rod together had failed due to corrosion (I am not sure what this rod is called, it is the vertical rod that goes down into the lower unit, it has a coupler that joins two pieces together and there are two small roll pins in there that act like set screws) the roll pins are small and made of steel. I had noticed some rust appearing on the shaft as soon as we put the boat in the water. It seems incredible that tohatsu would have such a weak link in an otherwise beautiful motor. Is this normal? what is the best course from here? I fell I should replace the ones on the other motor now, since it is rusty looking as well.

EDIT: When I changed the factory supplied LU oil,on this same engine, it was milky. Serviceman has it now. Could these two issues be related?