Whenever it shall appear to the Secretary of the Interior, or such officer as he may designate, that a clerical error has been committed in the entry of any of the public lands such entry may be suspended, upon proper notification to the claimant, through the local land office, until the error has been corrected; and all entries made under the preemption, homestead, desert-land, or timber-culture laws, in which final proof and payment may have been made and certificates issued, and to which there are no adverse claims originating prior to final entry and which have been sold or incumbered prior to the 1st day of March, 1888, and after final entry, to bona fide purchasers, or incumbrancers, for a valuable consideration, shall unless upon an investigation by a Government agent, fraud on the part of the purchaser has been found, be confirmed and patented upon presentation of satisfactory proof to the Land Department of such sale or incumbrance: Provided, That after the lapse of two years from the date of the issuance of the receipt of such officer as the Secretary of the Interior may designate upon the final entry of any tract of land under the homestead, timber-culture, desert-land, or preemption laws, or under this act, and when there shall be no pending contest or protest against the validity of such entry, the entryman shall be entitled to a patent conveying the land by him entered, and the same shall be issued to him; but this proviso shall not be construed to require the delay of two years from the date of said entry before the issuing of a patent therefor.