Even after separation, the concerned person's name has been appearing in the subscribers' list being updated to EPFO along with contributions for a few months. As a result, the PF records will reflect his services with this employer. However, this is not an issue unless he has taken up employment elsewhere before the date when such wrong continuation of PF subscription was noticed. If the other employer has already done compliance for him, it would result in double contributions against the same account. This could be resolved through account reconciliation, though it may not be a legal issue if the omission was bona fide.
The concerned individual may seek assistance from both the current and previous HR departments and approach EPFO for the correction of this mistake.