No clue why this would happen.
Currently have hundreds of people using this without any reported problems. Quite a few raves and contributions though.
Simple fact is the bookmark system pulls the bookmark Site Name and URL from your own site. There is no other way the bookmarks get their information. Please feel free to scan the code to verify this. The source code is open to you through your Admin Plugin Editor. We have nothing to hide.
There are no default settings at all either.
You might consider the possibility that your computer or browser has a virus or adware attached to your bookmarking system. Especially if the symptoms changed on their own after a period of time as you stated. I'd bet other bookmarks go to that site now as well.
Otherwise, as I said, I have no idea why this would happen for you.
If others are experiencing similar problems we would like to know.
We pride ourselves in good clean code.