If you create an Automation Rule leveraging the "Comment on Work Item" action and have the "Prevent duplicates by only adding this comment once to a particular work item.", you will be unable to add additional comments to the work item regardless of the contents of the comment.

The wording of the option can be understood to mean that it will add more than 1 comment via this automation rule if enabled, but only if the contents are different. But based on testing it will only add a single comment to an issue regardless of if the content of the comment itself is different.

It would be helpful to reword this better to ensure that there is no ambiguity around what this option does and not that the content of the comment itself is irrelevant as it pertains to this action.