Permission on Database
Most probably because you are using the generate scripts method to do so.

I would suggest to use open source DBA tools to view the permission or export.

Aliases : Export-SqlUser

Synopsis

Exports users creation and its permissions to a T-SQL file or host.

Description

Exports users creation and its permissions to a T-SQL file or host. Export includes user, create and add to role(s), database level permissions, object level permissions.

Example:


  PS C:> Export-DbaUser -SqlInstance sqlserver2014a -User User1, User2
  -Path C:\temp\users.sql


Exports ONLY users User1 and User2 from sqlserver2014a to the file C:\temp\users.sql