Keep horizontal flip when exporting DNG to JPG

I have photographed a lot of old film positives which somethings where photographed mirrored (wrong side up). In bridge I can open the photos is Camera Raw, fix them, crop them and flip them. I also add Meta data such as description and when the original phot was taken. Bridge are showing these changes but when I choose to Export the originals/DNGs to JPG and preserve all Metadata and as high quality as possible the cropping, adjustments and added text follows to the JPG but the horizontal flip does not. How come and how do I fix it?