The issue raised is, as I am able to understand, not the forfeiture of gratuity but only whether the period of absence during say 2013 to 2017 due to the operation of the punishment of dismissal that was set aside later should be included in the qualifying service for gratuity or not.
When the award mentions " reinstatement with back wages", it would automatically imply "reinstatement with back wages and continuity of service with all attendant benefits". In the absence of the grounds of challenge against "the payment of back wages" part of the award that is not made available for perusal, one has to presume that the Labor Court might have set aside the punishment of dismissal in its entirety and hence the direction to reinstate with back wages. Otherwise the Court would have modified the punishment as excessive and would have ordered no back wages or lesser rate of back wages under the powers vested in the Court u/s 11-A of the I.D Act,1947.
Coming to the dismissal proposed at present on some other grounds of misconduct, the poster needs to explain why the management raises the issue of exclusion of the individual's service from 2011 to 2017 based on its pending appeal against the back wages part of the award. If one dwells deep into the sweeping meaning of Sec.2-A of the P.G Act,1972, one cannot escape the conclusion that the absence of the incumbent say from 2013 to 2017 due to the punishment of dismissal which was subsequently set aside by the Labor Court has to be notionally treated as continuous service only. Even if the appeal of the management regarding the issue of back wages succeeds, in my opinion, it can not alter the factum of continuity of service of the individual.