Answer (1 of 14): The term “continuity error” gets thrown around a lot in reference to Trek, oftentimes erroneously.
Some of the most famous “continuity errors” can be explained with a little imagination and common sense.
WHY DOES KHAN KNOW CHEKHOV IF CHEKHOV WASN’T INTRODUCED TO STAR TREK UNTI...
Is the cannon explanation for tos to tng change being a skin disease or something that has infected the whole population?
No that is actually somewhat the explanation why they look more human. It is explained in Enterprise, the Klingons try to create some super soldier serum, but that kills them. Phlox helps them create a cure, but that makes them look more humanoid. I think at the end of the episode they say that it might take centuries to revert this effect
Enterprise established it as a result of Klingons experimenting with human augment DNA and it getting out of hand. It probably didn’t need to be addressed in universe, but I thought it was a fun retcon.