Digging through a bag of 1943 wheats, I found this. The "4"and part of "Liberty" has been sheared off.
It's pretty corroded so it's difficult to tell. When I tilt the coin in the light, I can see remnants of the 4. My guess is that it was sheared off (PMD) but because of the condition, it's only a guess.
The 4 on the 1943 cents seems to be a common "attractor" for grease for some reason. I have seen a lot of 43 cents with the 4 missing including in high grade where it definitely wasn't a case of the 4 being scraped off because the zinc plating is intact.
I agree with you. I have one or two others like that. This one has the pebbly surface so ít's difficult to tell what actually happened.