This issue was fixed in Patch 1.17.7
In your workaround, as long as you are telling people to use cheats, you might want to provide a different solution which doesn't require leaving and rejoining the career:
Traits.equip_trait trait_Hidden_HasBeenScientist
The game added a new hidden trait, trait_Hidden_HasBeenScientist, to track if the sim is capable of creating serums. That trait is granted when the sim first enters the Scientist career, hence why the workaround works. But the only thing that should be required for the fix is granting the trait.
Caveat: I tested only the adding the trait part, as I don't have a previously existing sim in the Scientist career (and thus with the bug), but it should work.
Thank you for that solution.
That is good to know as there seem to be other problems with the science career that might have the same source.
I shall try on a game I have that has other issues.
