Is anything wrong with hiring TA as a private tutor?
As a lecturer, I would feel that my TA possibly has a conflict of interests if they are also working as a tutor for one of my students. Among other things, TAs are often asked to solve through the final exam, to check correctness. So even if they are not involved with marking, they have access to confidential materials, and they can inadvertently leak some of this knowledge to the student they tutor.