I just tested it:
the reason is the bloom shader. ( I removed it, and the game
feels fine when playing...)
This might cause a delay in the actions verus the visible frames.
So the movement appears some frames after moving the object.
Its not really the FPS, as i can run it with about 50FPS with
the bloom shader. and 60Without,
but the lag can be felt with bloom on.
(maybe useing the time_step then gives wrong values when
the displayed framelenght is different to the actual one...)
Easy Fix: just make the bloom as option in the setup.