I just ran a quick test in workfront by typing in an update on the project updates section, then, clicking to the project's program, then using my browser's back button to get back to the project updates page. I also just tried refreshing the updates page (F5 the browser page). During both those actions, the comment continues to "stay put".
Have you tried any troubleshooting, such as clearing your cache and cookies or trying a browser you don't normally use -- or do you remember adding any new extensions (or have your IT team added any new extensions) to your browser?