There is nothing illegal or wrong in PF contribution by an employee who is receiving PF Pension. Only thing is that employer's contribution to Pension Fund @ 8.33% shall not be made for him. After all, Provident Fund is a kind of savings or investment and an employee shall not be denied to contribute towards it due to his age.
EDLI contribution shall also be made by the employer in respect of such employees.
Regards,
Madhu.T.K