Why does list columns appear twice after powershell export / import script execution?

Question

i tried to write powershell scripts that export and import site columns and content-types (from this article and this) from a SharePoint 2013 Site (RootWeb) from the site-collection A to the site-collection B.

When i execute these and export all the stuff and import it back again within sitecollection B, I have some duplicate fields within the new lists in sitecollection B. At the following pictures you can see a custom folder content type that inherits from "folder" that has two fields where users have to input a name:

What is happening here? In list-settings and content-type settings i see no duplicated fields? I do not understand where is the problem, what did I do wrong?

Any help is highly appreciated!

EDIT:

The xml that i have exported for site columns (to import it later) does not contain standarad SharePoint columns like Name (FileLeafRef). But, the exported content type xml does use these standard columns from SharePoint, see:

https://i.stack.imgur.com/YFsSz.png

Where is the mistake?

Thank you.

Answer 1

Make sure you export only site columns that are custom columns and not site columns that are a standard part of the SharePoint installation.

For example, the fields named LinkFilenameNoMenu andFileLeafRef are built-in columns in Sharepoint so you don't need to export them; they will already be in the destination site collection.