I have created a Document Library Template using "Save as template" option from library settings page.
When I create a new document library using that template it shows a site columns internal name instead of display name.
The template source document library is using Content Type containing a site column Document Category. This Document Category column has internal name AbcDocCat
So, overall the new document library shows column with AbcDocCat instead of Document Category, and this is the issue.
SharePoint Environment: Office 365 SharePoint
(1) I created site column with name AbcDocCat and later renamed to Document Category, to keep internal name clear.
(2) The field name appears in ContentType as Document Category, so this could not be cause of issue.
(3) The ContentType is at site collection level and not at Content Type Hub