My images start off as PNG's with no background and once edited and exported out of Lightroom, they have white backgrounds added. Save transparency is selected and in the past, never had this issue. This is a bug
The issue started when I updated my Lightroom from version 5.5 to 6.0.
With version 5.5 I could export my TIF image with a transparent background with 'save transparency'. After updating it to version 6.0 and following the same steps (Importing a picture with a transparent background, then exporting it in TIF format (that was original) with 'save transparency') it exports the image with white background! HELP!