Or they just flat missed, got a hit on a thick coat but failed to hit the body inside it.
Andrew Jackson won a Duel because he wore a loose cloak that obscured his stance and body position. He was hit in the chest but not dead center. His opponent was a pro and renowned marksman. Had the opponent had a clear view of Jackson's torso he would have centered him and the duel would have been over. As it was Jackson though wounded took his time and delivered a fatal shot.
another factor to consider is that many NK & Chinese troops would tuck a piece of scrap metal inside their coats as makeshift body armor. That could also explain part of the M1 carbine ineffectiveness myth.....
Theres a Japanese entrenching tool with two holes in the blade. At one time some thought these were so a soldier could use the blade as a face shield when looking over a parapet, but it turned out the holes were so you could pass a cord through it and sling it from neck or shoulder for quick use. If worn in front the blade would offer some protection for the torso from bayonet, grenade fragments, or pistol rounds.
One selling point of the M1 Carbine was that it would penetrate the various known body armor types available before and during WW2.
In USN tests the Japanese armor stopped the .45 ACP fairly easily.
Some photos from the Japanese occupation of China show Japanese officers wearing elaborate steel breastplates over their uniform tunics.
The .357 would be unlikely to out do the carbine, but would out do the .45 ACP in penetration of body armor, helmets, and the sheet metal of light vehicles, just as in civilian LEO applications.
At some point a gasmask pouch was available with a pocket at the back for insertion of a thin manganese steel plate, don't know if these were ever used.
The British Manufactured thousands of reinforced fabric Chem armor vest near the end of WW1 for a final big push that proved un necessary.
Also the U S technical manuals on small arms ammunition list a number of non standard rounds for use in non regular issue handguns in inventory for un specified reasons.