It's not the slide show after all, it's the colour change.
Go to SETTINGS. Go to PERSONALISATION Click on COLOURS then switch to OFF "Automatically pick an accent color from my background"
That seems to do it. You can still then have a background slide show if you'd like to.
Please say if this works for you.
Thank you so much!!! This was the one that worked. I disabled the slide show, it kept happening, but this one was the answer. Futhermore, if you disable this, and then choose a color, it happens again but only that time, for example, you scroll down, choose the color red, check again and it´s up. Scroll down again and other color, the same. Scroll down, do nothing, stays where it should, so that proves me this was my problem in Windows 10, I don´t know in the other windows.