Since updating to the latest Lightroom CC my PNG exports have had a partial background that looks like it could be a "content aware fill" that I didn't initiate. It isn't there in lightroom but is there in the PNG file after export.
Attatched file is a screenshot of the exported PNG opened in Photoshop.
It is transparent in the upper left corner and along the top and in the upper right bolt hole of the license plate. The other 3 holes have been filled with jaggies and also around the bottom and right side of the image.
By after I mean after I have exported the image from Lightroom. The background was eliminated by "edit in Photohop" from within lightroom and is completely gone in both places. Once exported however, the above result is what I get.