Problem scenario
You clicked "Update file" after you made changes to a .php file in WordPress (via the Theme Editor). You have refreshed the web page, but the changes have not taken effect. What should you do?
Possible Solution #1
Can you update the theme? If the theme has an update waiting, getting it updated can fix this problem.
Possible Solution #2
Clear the history of your web browser.
Possible Solution #3
Wait for some time. The problem may go away.