Interesting, good to learn as I've never heard of it until now! Funny, I was wondering why the planchet was so thin, makes sense now!
If you CRH, you are going to find these. I suspect I’ve found 3 or 4 cents and at least one dime over the years. The first cent I found was razor thin with full patina. I was around 14 at that time and certain I found a rarity. My trip to the LCS brought me to some reality and an education. After that, finding more solidified the theory. I would even say that aside from the significantly reduced specimens like this one, CRH enthusiasts see dozens of etched coinage that looks odd but remains closer to intact. It’s not uncommon in my experience especially when we see these posted by others here at CT.
Chemical corrosion caused by diluted and agitated acid. Acid will dissolve the affected surfaces equally reducing diameter and thickness. A weakened and agitated acid solution will prevent gas bubbles from adhering to the surface of the coin preserving and in some instances enhancing detail.
Here are additional pictures with a comparison dime. Same diameter, less than half the width and weight (dime is 2.5 grams and this cent is 1.1 grams).
if this were struck on a foreign or dime (us) planchet, more details would be missing since the width of the coin, or thickness would not allow for a clean strike, i agree, acid dipped
not necessarily. lots of foreign planchets struck by U.S. dies have no missing details and decent strikes
of course there are exceptions to every rule, but the majority of the ones i have seen on internet and for sale have had this effect showing