You can thank an edit again after thanking it once. However, excessive thanks neither notify the other person nor appear in Special:Log.
This bug appears about months ago.
**Steps to replicate the issue** (include links if applicable):
# View the history of any page, choose an edit to thank, then click the "thank" link at the end of that edit.
# The person being thanked is notified.
# Open Special:Log, select "Thanks log", your can find your thanks in it.
# Refresh history page, then thank the same edit again.
# Refresh the page and thank again. This time, open the "thank" link in the new tab.
**What happens?**:
# When you refresh the history page, the "thank" link is still clickable. Clicking it allows you to thank in-page.
# If you open that link in a new tab, a big blue "Send thanks" button still appears.
# The person being thanked is not notified again. More thanks will not appear in Special:Log. (Which is expected behavior.)
**What should have happened instead?**:
# When you refresh the history page, the "thank" link you have clicked should turn into a "thanked" text.
# If you open that link in a new tab, the blue button should not appear.
**Software version** (skip for WMF-hosted wikis like Wikipedia):
Can reproduce in Wikipedia.
**Other information** (browser name/version, screenshots, etc.):