Maryland Code, Real Property § 7-103

(a) The title to any promissory note, other instrument, or debt secured by a mortgage, both before and after the maturity of the note, other instrument, or debt, conclusively is presumed to be vested in the person holding the record title to the mortgage. If the mortgage is duly released of record, the promissory note, other instrument, or debt secured by the mortgage, both before and after the maturity of the promissory note, other instrument, or debt, conclusively is presumed to be paid as far as any lien on the property granted by the mortgage is concerned.

(b) After an assignment of a mortgage is recorded, any payment made by the original mortgagor to the assignor is effective to reduce or discharge the note or debt, unless the mortgagor has received actual notice of the assignment prior to the payment. This provision also applies to a payment by a transferee of the mortgagor's interest in the mortgaged property except where the assignment of the mortgage is of record at the effective date of the transfer of the mortgagor's interest in the mortgaged property.