It was my understanding that in Ep.5 (Empire Strikes Back) that carbonite freezing of living beings was a brand new idea. They did a lot of probing and testing on Han Solo to see if he would be able to survive the process. And even once he was frozen, there was still doubt as to whether he survived.

 

In TOR, it seems this process is incredibly common with no margin for error. Seems like a bit of a lore breaker to me.

The dark age during the New Sith Wars probably destroyed any knowledge about Carbonite freezing

The idea to freeze living beings in carbonite might have been forgotten during the more peaceful times of the Republic (after 1,000 BBY).

 

But it could have been preserved by the Sith until Darth Vader reintroduced it to the galaxy at large at Bespin.

 

That's just a guess, of course.

It's not the process itself that's the worry, it's the equipment.

 

At Bespin, their carbon-freezing systems were not calibrated for use on living organisms. Ergo, Lando wasn't sure if Han would survive if they froze him there...as he wasn't non-organic.