Cannot add Inline comment (plain text)

Steps to reproduce - Part 1.

1. Create a page in confluence
2. Add some text, natural english would be good. Make it of a decent length
3. Save the page
4. Get a new tab and open the same page again.
5. Note: you should now have two tabs with the same page 
6. Pick one tab and edit the page. 
7. Add the letter 'e' to the page somewhere
8. Save the document
9. Go to the other tab, don't refresh and select a random letter 'e' from the text
10. Once selected choose to insert an inline comment
11. type text
12. Click to save
13. Observe strange error message

This will work with words as well. The key is that you need to add a new instance of something so that more than one exists on the page. The root cause seems to be that inline comments don't take into consideration that content might have changed the page in some way. If data it sends to the server doesn't match what the server has then you'll see this message.

Steps to reproduce - Part 2 

1. Create a confluence page
2. Insert a Jira issue macro, have it display as a table with a summary etc
3. Add some content underneath the macro that uses some of the same words as are in the issue
4. save the page
5. Select one of the letters, words or phrases in the page that also exists in the Jira issue.
6. Try to insert an inline comment
7. Observe failure message

Original Description 

Original steps to reproduce:

1. Create a new page.
2. Import a word document.
3. Mark some plaintext (no macro or user mention visible) and create an inline comment.
4. Save the page.

Other reported steps:
1. Insert a link into a page
2. Add inline comments to an individual word, or word fragment (not multiple words). The highlighted copy should be anywhere on the page above the link

Customers have also reported seeing this issue without having added links or imported documents to their page.

Expected Results:
Comment should be saved.

Actual Results:
The following alert shows up and the comment is not saved.

Alert:
We can't add your inline comment; the section you highlighted may contain a macro or user mention. Try highlighting plain text.

Note: Even if I retype the affected word ("West-Balkan") in another part of the page, the result is still the same.