Slideshow on Apple TV not working well

I have had this problem for a long time: whatever settings I use for playing a slideshow on my Apple tV, it is not played by the rules I get the same picture shown a number of times even though 'repeat pictures' is switched off. And some pictures are not shown at all. In the past, I could force a good slideshow by setting the time per picture to 3 seconds. But this does not work aymore as well. Anyone a clue?