Okay, maybe I'm just not seeing something here.
The first coin photographed is EMDS to MDS at the latest. There's no way
Die Deterioration could have caused the effect spotted on this coin. The second coin is actually later die state than the first, and the digit is thinner. How do I know this? Look at the outer edge of the design on both coins. The top photo shows very little sign of die flow lines, thus HAS to be quite early die state. Die age is determined by these lines, and here they are almost non existent. On the coin in the bottom photo, the lines are present but are not heavy. This is evidence that the top coin was struck by an 'earlier' die than the bottom coin.
Having said that, I have seen a number of coins with slightly weak strikes that have outer devices that appear thicker than those on fully struck coins. This tends to be the case especially with the motto on the obverse of 1962-1968 cents, where an incomplete strike leaves the letters shorter in relief than they should be.
The reason for this effect is quite simple, actually. A weaker strike keeps the design from striking up into the die completely. Since the letters are all bveled so they don't stick to the die, a cross-section of any detail on the coin will look like a trapezoid. For those who may not know, a trapezoid is a shape with a wide base, and angled sides that come to a smaller top than the base. Because of the shapes of the letters and the fact that they are beveled, if you shave off some of the top of the letter, the result will be wider than before. Shave more off, and it becomes even wider. The more you shave off the wider it gets, until you reach the base.
That's what happened here. The fact that the top of the 8 is flattened and mottled tells me this is bare planchet that has not been struck, thus it never met the full recess of the die. Because this 'top' stopped before reaching the full extent of the cavity in the die, it's wider than a 'normal' top. That's all.
The light doubling on the left side of the 8 is eject doubling. It can be very minimal, and it can affect only one letter. I can tell it's eject doubling because it is curved, not flat.
Something of note on all 1958 cents is the fact that there is master die doubling to some extent on all 1958 cents. This happened when the date was doubled mildly on the master die. This doubling transferred to all working hubs and working dies, and depending on the age of the working hub when it created the die, and the age of the working die when it struck the coin, the effect can be very visible or nearly invisible. Anyhow, when it does appear, it is a slight hook, part of a curve, on the upper part of the 8.
Another note to make is that many 1958 cents have what was improperly listed by Breen as a 1958/7 (8 over 7). This anomaly is a master die gouge, which like the master die doubling, transferred to the working hubs and working dies and can be more or less visible depending on the hub's age at the time it made the die and the die's age at the time it struck the coin. When visible, it appears as a small 'horn' shape, or point, on the upper right edge of the 8. Because some of the slabbing companies would list Breen numbers on the slab labels, some people had these labeled as Breen varieties and sold them for quite a chunk of change - considering all 1958 cents show it and it's not a variety to begin with.
That's all I have.