When I export an image with "Export as" as jpg and change the image size in the dialog to something smaller, a grey 1px border is produced. I suspect it has to do with the white background color that is used for transparent pixels in jpg.
Is it possible to change the matte color for jpg in the "Export as" dialog?
When choosing "Save for Web (Legacy)", there is no problem and also pngs work fine. I could also make a slightly smaller canvas size to cut off the light edge but that's just a bad workaround.