KLWP not saving

I've been working on a new preset. As it is a work in progress I'm using another preset as my current wallpaper and I save the new preset as I get another step completed. However, the save function doesn't seem to be working any more. I can save and minimize the program and see that the change I made is on the actual wallpaper. I then open KLWP again and load my regular wallpaper preset and save to set it as active on the phone. When I go back to work on the 'in progress' wallpaper the changes I made a short time ago have disappeared. This is the same steps I've used in the past to save progress. It may not be the most efficient but it works, or used to. Please help.

I'm using version 3.39b911019 PRO and my phone is a Samsung S8.