Can't save/commit edits in web interface

If I edit a file in the web interface and hit “Commit Changes” the page hangs for a minute or so, then reloads the page with the banner telling me it saved successfully. The problem is no changes are actually saved. I’m at a loss as to where to start troubleshooting this. I have not found anything that seems relevant in the logs, nor have I found any posts of similar issues.