I've been trouble shooting this for a while now with no luck. I have multiple slide shows on my site and for some reason two seem to be linked in some way. They're on completely different pages and I've deleted and recreated them both with no luck. At one point or another one slide show will display slides from the other slide show. They'll be warped because the slide show dimensions are different and the other slide show will be acting normal. So basically both slide shows will only show one sets of slides at any given time. here are pictures of each scenario.
Did you try to delete all pictures from all slideshow and start from scratch with yet empty slideshows?
Sometimes I see this issue on tablets. It happens, when RAM is getting short. Normally it helps to clear the caches and/or restart the device. Give it a try on your computer!
Usually, the reason is that the same file names are used for different images. The name of each image must be unique.