Cannot rate already rated thread

[Karlos]

Once a thread has been rated it becomes impossible to add further ratings

See summary.

Also see: http://www.vbulletin.com/forum/project.php?issueid=28714

[Karlos]

A bit of google-fu reveals that this appears to be a known issue that crept in from 3.8.3 to 3.8.4...

[Karlos]

I've manually patched the issue for now, based upon the information given here:
http://www.vbulletin.com/forum/project.php?issueid=36877

For myself, the patch seems to have worked in that I could now rate a thread that had been rated, but a second attempt to rate it informed me I had already cast my vote.