I am not familiar with the GENX, but I have overhauled this part on the PW4000 and GP7000. I have been out of the business for 4 months and did not hear about this. Wow, thats bad.
In reading the related articles it appears that GE
is making a change to the antigalling compound that goes on the splines and the threads of this part. It mentioned that they are going to change to one that has more lead. Apparently, this caused galvanic corrosion. This happens when dissimilar metals are in contact with each other. This part is made from titanium, and mates with the nut and LPT shaft, which are steel. Also mates with bearings. This part is not coated on the shaft. Just antigall on the splines and threads. LPT shafts are coated, but not on the splines. The splines also have antigall.
uses several types of antigall coatings on their engines, depending upon application. Looks like GE
chose the wrong type initially. Maybe they changed the alloy of one of the parts from a previous engine which they were familiar with, and assumed it would work the same.