An error of EntitySynonymMapper

I have configured the synonym mapper as follows:

  • name: EntitySynonymMapper

and edit a synonyms.md dataset:

synonym:許國瑞

  • Jeff
  • 國瑞

synonym:鄭國威

  • Jeffery
  • 國威

Jeff should be the synonym of 許國瑞. Jeffery should be the synonym of 鄭國威. However, the RASA NLU model maps Jeffery to 許國瑞. How could this happen? Jeffery is a different name from Jeff.