It is not common. Hair goes through the generating phase-> growing phase -> degenerate-resting phase about 25 times.
If you go through all of these processes, your hair will no
longer grow. Therefore, if the hair follicle is damaged during the surgery, or
if the number of available hair cycles is reduced, the transplanted hair may
fall out.
If you are concerned that your hair loss may have continued to progress
after your transplant, you must keep in mind that post-transplant care is
important.
You can maintain satisfactory results for a long time if you
continue to assess and prevent hair loss.