Not sure if this is 100% confirmed to be resolved now, since the post mentioned above (“Please see the post below…”) has many replies of users where it’s still not working.
The big question: while this is being fixed, what do you recommend we tell all the users of our libraries? We have thousands of components across dozens of libraries used across hundreds of files. Should we advice everybody to NOT accept any library updates until further notice? Or to not work at all since they will have to revert to pre-Jan19 versions?
EDIT: I got the courage to re-publish the affected component sets to try on a few affected files and it seems that it’s retaining overrides! 
Now I have to redo the changes I wanted for those components and see if those changes don’t reset overrides again.