Mmm, wait, are you actually creating a slideshow (by selecting photos and clicking the new slideshow button, so that there is a new slideshow listed in the left column), or are you clicking the play button with some pictures selected or in an album?
Either way, if the Ken Burns item is unchecked, *AND* the scale to fit screen item is ALSO unchecked (oddly), then I don't get any motion. You also have to use a transition that does not itself involve motion (e.g. dissolve).
I'm also on 6.0.5.