Written by Thomas Speekenbrink
If you want to replace an import file in the Web Interface of Google Drive it will not overwrite the existing file but a second file is created. This is because Google Drive does not work with file names but with file id's
If you want to upload a file by using the Web Interface of Google Drive you have to do this through Manage Revision - Upload New Version in Google Drive.
More details can be found in this article: replace google drive file with new version
Note: This issue does not occur when using the local Google Drive application.