What is the legal consequence when a wife, appointed to divorce herself using the phrasing 'Divorce yourself according to the Sunnah,' claims to have effected three divorces?

Primary text

If a wife is instructed to divorce herself using the phrasing, 'Divorce yourself according to the Sunnah' (Talliqi nafsaki talāqa as-sunnah), and she subsequently claims to have enacted three divorces, only one divorce has legally occurred. This ruling is maintained because an agency of divorce (tawkeel) specified by a general term applies to the minimum number implied by that term, which is one divorce. Furthermore, the correct Sunnah divorce, according to the sound opinion, is a single divorce effected during a period of purity in which no sexual intercourse occurred.