Exporting PDF using a placed masked image with adjustment layer, i.e Brightness/Contrast, the adjustment is applied on the Publisher page background.
Placing the same image in a Photo document, exporting PDF is just fine.
Coming from Photoshop and InDesign, adjustment layers are never done on transparent (i.e going "though" the image and passed on to the Designer background). This issue was a bit tricky to find due to the fact that it has never been an issue in other apps.
Zipped file with example files Publisher/Photo and an Image with adjustment layers.
I know that there are workarounds, but this bug has to be fixed.
Adjustment_layer_on_transparent.zip