Dark Brotherhood bug - Contract Glenumbra

Tholian1

I was doing the repeatable contracts and got one at Daggerfall Castle in Glenumbra. It says to kill Isabeau Jend. She is in the throne room and only walks back and forth between a shelf and the king, but when she approaches the king's throne, she vanishes and reappears as she returns toward the back of the room. There seems to be no way to kill her without witnesses.

peacewishes

I'm having this problem too.

Organic

The same thing is happening on the PC side. Only when she's about to vanish am I even hidden long enough to strike. Even trying to kill her WITH witnesses is impossible as I'm never hidden while behind her.