1988-D LMC And 1984-D LMC Unlisted RPMs

Which one? The 1984? I can see that if it weren't raised.
I am uploading a better closeup pic of the first 1988D, but that certainly does not look like a plating issue.
The 2nd 1988 can't possibly be anything other than an RPM. I see three distinct Ds, one too close to the 8 (the bottom curve of which is in the final D) and one on an angle, with the bottom serif touching the final D.

I see the damage being zinc rot but not the multiple Ds. Or does zinc rot create extra mintmark images? I would like to know how...

The first 1988 doesn't have exposed zinc. It might be Machine Doubling, but if it is I would expect to see more examples on the obverse than just the mm.

The 1984 with exposed zinc fits the known pattern of split plating.

The 1988 without the exposed zinc actually is consistent with the doubling of the D in the 1988D DDO-001 & 002 on varietyvista. Looking for other markers...

And I still want to know how rot can create multiple images of a mintmark in various locations and aspects. Please explain.

I believe the first 1988-D is either a late die stage of 1998-D DDO-001 or it is a new DDO from an older, over-polished obverse. There are very heavy polish marks across the entire face.

The letters in the motto appear almost polished off, the one of 1998 is too thin, the top of the 9 has bits missing and the eights are... weird.

The tail of the 9 is doubled and there appear to be die chips in the 8s along with doubling, but with more chips than in DDO-001.

There is a bit of a doubling effect still visible in a couple of the motto letters, consistent with DDO-001.

Even the DDO? Yessir, it is not a plating doubling. It is a DDO, not a RMM or plating doubling. I will start a new topic for that one.

So you're saying zinc rot created the curved bit of copper inside the D (oddly consistent with the bottom curve of a D) and the flat bit of copper adjacent to the D? I hate fool the eye stuff like that.

1984-D is a lost cause. I concur with the consensus on split plating. I also can imagine with your display of bubbling that the plating under the bubble within the mintmark could be flipped up into that curve that looks like another D so I will spend that puppy before it disappears...

My focus is now on the poss late stage DDO-001 on the other 88-D. I am going to shoot an email to Dr. Wiles to see if he wants to look at it.

The 88 -005 you're showing is the Philadelphia mintage, not the Denver, correct?