Player character is able to move and turn when it shouldn't.

[willy wnanna]

It is not game breaking but funny and annoying bug: during scenes like during thief guild mission Speaking With Silence when Mercer talking with Karliah and when turn into animal by Brelyna during mission Brelyna's Practice, I was able to use WASD key to move around. Also during Flower Girls' scenes I able to use WASD to freely turn around my player character (not move around though only turning around). Any idea what is causing it?