It seems that links in comments are not tracked for changes.
It's reproducable on 2.1.8, 2.3.2, 2.4.3 (confluence.atlassian.com)
Steps to reproduce:
1. Create a page A1
2. Edit page with content: [A1]
3. Add a comment with content: [A1]
4. Edit page A1: rename A1 -> A2
Expected:
1. link in page body changed to [A2]
2. link in page comment changed to [A2]
Actual result:
1. link in page body changed to [A2] as expected
2. link in page comment is [A1] and added with plus which is wrong.