Villager Zombies don't have a skin when they are de-zombied. You are left with shadows running around on the ground. While it is incredibly funny and cool it is almost absolutely a bug.

Unable to reproduce this - if it consistently seems to occur please upload the world in which this is occurring and I can try it out there.

Unfortunately I cannot get the ghost but I will keep trying. Possibly due to them being spawned in using an villager zombie egg but they do all come up missing a skin and with the name Steve the Farmer. This is the same name/profession as in my main world. No other mods. Forge 1.12-14.21.1.2413. Java build 1.8.0_144-b01.
MCA_villagerZombie_issue.zip