The was I control my character is maybe not very skillful, using the WASD keys and the mouse at the same time, giving out commands contradictory to each other, maybe because of this, sometimes one of the movement key imput values stuck.
Sometimes I notitce, that a character is moving somewhere without control. When this happens, mouse commands can only temporarily overwrite the movement (though entering doors or opening containers stop the movement), even hitting the key of the opposing direction, the movement is only temporarily overwritten. The uncontrolled movement stops as soon as I hit the key matching its direction.
I can think two different reasons for this to happen:
1. There is too many inputs, and the button-release event is somehow overlooked (less probable).
2. By rotating the camera, while a button is held, it is possible for a movement direction to change the key it responds to and because of this, the system expects a button-release from a different key, which can not happen, unless that key is pushed.