Hey guys,
I cleaned up the entire stage of guards, making sure each and every guard is hidden somewhere, mostly in dumpsters.. took my time and spent quite a few hours.
After I was finished I went to the high overseer office and for some reason after a second or so he immediately spots me and him and his guards start running. I don't even have the chance to poison his drink and it doesn't matter where I hide (even at the dark top area above them).. quite annoying.