Duplicate fileld fond in List item new form and edit form

Hi,

I have a custom content types which includes 4 column among which one is taxonomy filed, The custom content type applied to the site collection document library, but when we browse the New form or edit form of any item(document) in the site collection document we can found there is a duplicate taxonomy field that get generated automatically, though in content type it showing only one taxonomy filed as expected. 

How can I remove the duplicate taxonomy field from the new form and edit form, since many document are already associated with the content type I cannot delete the content type.