You may encounter the following error message when working with keywords in the platform:
An Attempt was Made to Create a Duplicate of a Keyword That Already Exists
This error is often due to Microsoft Advertising "normalization". Microsoft Advertising will remove special characters or extraneous words like "a" or "the", which then results in a duplicate keyword error. For example, uploading "the red shoes" when red shoes already exists in the account.
Click here to learn more about the Microsoft Advertising normalization strategy on the Microsoft Advertising blog.
How To Fix The Issue
No fix necessary, this is expected behavior.