Today I was updating/deleting some tags from old posts (some categories too). I updated a LOT of very old post, and all of them were published to my facebook fan page!
The only thing I did was adding or deleting categories or tags, so there wasn't any "publish again to facebook" option (as when updating post content).
I had to delete all those posts from my wall, I almost went crazy :)
The only way around this right now, is disabling the plugin when I plan to udpate tags or categories, but sometimes I forget about that and BAM! lots of very old content in my Facebook wall (some dating from 2007!!!)
Hope you can fix this or provide a way to avoid it.
Sorry about my English, hope you could understand what I meant.