Track changes no longer displayed

Actually, the most recent update to Mac Office is 16.114.3 which was pushed out on 10/27. You may want to apply that then restart the Mac to see if the issue persists. Confirm that your flavor of macOS is fully updated as well.

Although there is an AI bot response to some questions this is primarily a peer-to-peer support site hosted by Microsoft. Replies typically are not immediate. The time frame varies depending on contributor participation, so new questions may not be seen by someone with a reasonable response for some time.

The AI responses show a user name of AI answer & are displayed against a gray background.

Could you please confirm whether the issue also occurs in a completely new blank document, rather than only in documents containing existing tracked changes? For a quick test, create a new document, enable Review > Track Changes, type a sentence, and then delete part of it. Next, open Review > Reviewing Pane and check whether Word records the insertion and deletion.

One additional setting worth checking is Review > Show Markup > Balloons > Show All Revisions Inline. Microsoft documents that deletions displayed in balloons may not appear as strikethroughs within the document itself. You can also open Word > Preferences > Track Changes and review how insertions and deletions are configured to appear. If the changes are being recorded but the expected formatting is missing, please share a screenshot showing the Review tab and a sample revision, without including confidential document contents. Keep in mind that Microsoft does not guarantee tracked changes will always appear in red, since colors can be assigned by author.