If you chart out the possibilities, a minimum of three, then the solution becomes obvious.

How?

Chart the possibly cases, assuming each is a Truth-teller and another a Liar. Do not worry about the Half-Liar because that would be the logically third person not selected.

Chart each job versus the person. Where there is a contradiction, that chart tells the assumption is incorrect.

So the only thing we know, that A somehow knows what B will say. Therefore i don’t see a mistake in the riddle. And even if something needs to be improved, than it is that the truth teller is defined as someone who tries to tell the truth and won’t tell knowingly a lie. ]]>