Don't waste your money on purple gold.
Likely, the "eating itself" you're seeing is the machine work when the housing is machined out to accept the LSD components. Manufactures leave those sharp/thin casting areas alone. Some areas show through more than others because the cast part is not perfect. The LSD in my 05 is that way from AAM.
I also just went down this road with my 05 after changing rear pinion seal but didn't post about it. The rear diff started making a weird growl sound when load was initially applied to the ring gear. Once ring gear had load, no growl. Pulled plug, it looked a little worse than yours. Dumbfounded at what the next step was, I pulled the carrier and pinion for inspection. Nothing wrong with bearings, races, or gears.
Went to a local guy who only works on manuals transmissions and axles. We talked through the scenarios, and it came down to fluid. I initially purchased 75W-90 SuperS synthetic gear oil because that’s what the service manual states to use, and that’s what the local parts store had. Local axle guy said never use synthetic gear oil, and only use the heaviest weight fluid you can find. So, I flattened out the crush sleeve some, set the pinion preload, set the gears back up, added 4 quarters of 85w-140 Castrol (non-synthetic) and drove it. Also changed front diff fluid to 85w-140 at the same time. Fluid was golden, but the housing and inside of diff cover had a brownish color film on them that wiped off easily.
The rear axle growling noise is now gone. I’ve pulled loaded trailers several hundred miles now without issues. I sent samples of the used and virgin 75w-90 fluid to be analyzed. The used fluid had a few more ppm of iron than the new fluid. But the new oil did have a low flashpoint, unlike the used oil. Apparently, a low flash point is not concerning, but notable. I won’t go into details about the gear oil lube discussion I had with the local axle guy. But his 40 years of knowledge opened my eyes to gear lube oils.
I've sense purchased two cases of 85w-140 walmart brand for the other trucks. Everything is going to have diffs serviced this month.
I was down to only my 91 12v for transportation. Motivation to fix the issue was great!