Desktop background

In WIN10 home I have set my desktop background to a slide show. The background photo is set to change 1 time per day and the shuffle is turned on. The shuffle works fine. The frequency of the background picture, though, changes a random times. Sometimes it change 2 or 3 times per day, sometimes, rarely, it changes 1 time per day. I have more than 40 photos (.jpg) the required directory.

Does anyone have any insight to this?

Thanks

Thanks, I'll check it out.

After 6 months I finally solved the problem.
The original location for my wallpaper: C:/Users/Shell/My Pictures/Rotating Wallpaper
I moved the sub-directory to C:/Rotating Wallpaper
I'm not sure why I did this, but now the wallpaper changes once per day.
I don't know if the instructions for doing this is specified my MS.