I've done some research on this and so far I can only find guidance for files and tabs:
Denoting a tab as being "unsaved" in a web application
Is there a better character than the asterisk to indicate a modified document?
However i feel my problem is different.
Here is an example of my configuration page. The user is able to upload 3 different files, for each upload they will need to click upload.
The user may also wish to view the content of the file before it is saved by clicking 'show current'.
Once the user has uploaded a new file but NOT clicked submit I want to show them that there are pending changes to be submitted
Question: How do i show this to the user? My research says I should use a red asterisk, however, on a webform, this normally means a required field.
The options i've though of so far are below: