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 good civilization.)
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.):

