The original or a certified copy of a conveyance, covenant, agreement, deed of trust, or mortgage, relating to land, that has been recorded in a county of this state other than the county where the land to which the instrument relates is located, is valid as to a creditor or a subsequent purchaser who has paid a valuable consideration and who does not have notice of the instrument only after it is recorded in the county in which the land is located. Recording a previously recorded instrument in the proper county does not validate an invalid instrument.
Tex. Prop. Code § 13.003