Ok, I got it why you said got addition word added to the end. For my situation is a little bit different. I would like to provide for those kinds of issues.
First of all what I need to do which is find back the old version because I have been format devices no matter laptop or smartphone. For example, this is my version
Release Release v1.40.113 (Chromium 103.0.5060.114) · brave/brave-browser · GitHub
Step 2 download a zip file because it can prevent auto-updated latest version. For me, I need to download the file name which is brave-v1.40.113-win32-x64.
Step 3 opened it paste down your old sync chain and use your smartphone to scan a sync chain to make sure you’re connected. Make sure your smartphone has been connected and check the sync chain you may see it added a new word in the end. For example, your previous version’s word count is 24. After your smartphone connected it would show our word count became 25.
*Note, you can check your current situation version in about brave. It shows you an error problem because the system cannot update its latest version.
Step 4 you can reinstall it again to your brave browser to the latest version. And use your latest sync chain code 
Step 5 enjoy it~ Please forgive me grammer mistake.