I have just tested this in Sitefinity 8.1 and I was not able to reproduce the issue. The value that is entered in the Author field is properly saved after the item is published. I am sending attached a short video for your convenience to demonstrate this.
Which is the Sitefinity version you are using? Do you receive any error messages while trying to publish the news items? Can you please try to edit a news item and change the value of any other field and let me know if the changes will be persisted after publishing the news item?
Please also delete the error logs under the ~/App_Data/Sitefinity/Logs folder (or save them to another location for a backup) and then try to reproduce the issue by trying to set the Author field and to publish the news item. Then please send me the generated files under the Logs folder. The error logs may contain more details about this and what might be causing it.
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