Works ok if played from slideshow module, but not impromptu..
win7/64
More info here:
http://forums.adobe.com/message/6037135
I'm sure this problem was introduced long before Lr5.4, but Lr5.4 is the first revision with a slideshow feature worth using (due to color/tone bug - thanks to Adobe for fixing) so...
Is there any way to manually advance a slide without a trip to the slideshow module?