I am using windows 10 and have the latest version of photoshop - when I export or use quick export to png my file is a perfect png but when I export using the "layers to files" option I end up with a white border around each element.
Can you post some screenshot with problem visible? It will be also useful to check and also post screenshot with Export Layers to Files dialogue open. There is option Transparency for PNG file format, have you checked that option?
The exact same thing happened to me and I never found out why. Mine were clean vectors imported from Illustrator and they never had a white backgroud. They were a series of icons and when I tested them on my website the white edge didn't appear. So it might be worth it to test one in it's final location.
The other weird part is if I exported them one at a time, the white edge didn't show.