All deeds, conveyances or contracts for standing or growing timber, or the bark thereon, which may have been proved or acknowledged by the grantors therein, and recorded in the office for the recording of deeds where such land is located, or which shall, within six months from and after the passage of this act, be proved or acknowledged and recorded in the manner directed by the laws of this commonwealth for the proving, acknowledging and recording of deeds, shall be as good and effectual in law, to all intents and purposes, as if the same had been proved or acknowledged and recorded within the time deeds are now required to be recorded: Provided, That nothing in this act contained, shall extend or be deemed or construed to operate against subsequent judgment, recognizance, attainder, forfeiture or lien whatsoever, or against any subsequent bona fide mortgagee or mortgagees, purchaser or purchasers, or any estates, lands, tenements or hereditaments mentioned or contained in said deed, conveyance or contract for timber or bark, before such deed, conveyance or contract was or shall be proved or acknowledged and recorded agreeably to the directions of this act.