(a) When any town clerk has recorded any instrument that the town clerk knows to be a release, partial release or assignment of a mortgage or lien recorded on the records of such town, the town clerk shall make a notation on the first page where such mortgage or lien is recorded, stating the book and page where such release, partial release or assignment is recorded, except that a manual notation of such release, partial release or assignment shall not be required if such town clerk provides public access to an electronic indexing system that combines the grantor index and the grantee index of the town's land records.
(b) On and after October 1, 2012, any document being recorded shall contain not more than twenty assignments of a mortgage.