You won't see an expand/collapse feature, but only the dots, meaning the unchanged content was hidden and reduced to (...) the three dots. If it has unchanged content, not even the format highlighted in blue, then it's a bug, and you can report it to Atlassian. Have a look; sometimes the content is part of a panel, macro, etc., and it will get formatted if a small configuration changes, giving you the wrong impression that nothing really changed but did indeed.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.