Currently, you cannot view recent mark-up activity on Sheets in the Activity Log. All published mark-ups should be traceable in the activity log, so that teams can verify RFI postings or other drawing updates by date completed, instead of having to open each sheet to verify postings. Adding Markup Activity to the Project Activity log would take the process of auditing RFI postings from a very tedious and manual effort to a quick glance to see a week's worth of postings.