Image has faint grey in footer when printed

Hello All,

I've been using the usual LR/PS duo for several years and almost always print from LR but this is something I've never seen. I've taken several images from LR into PS to add a 1/2 in footer at the bottom so I can put in the title of the image  in text. The problem I'll show has appeared in some, but not all of the images. I increase the canvas size to give an additional 1/2 in at the bottom. On most of the images I left this fully transparent-no color. But when I take it back to LR there is a light grey cast on the 1/2 in strip. It prints with that on the image. I hope you can see it in the attached image. I've tried running the eraser tool along the bottom before I bring it from PS but that did nothing. The strange thing is, this does not appear when the image is printed from PS. I've never seen this before but I don't often do this type of mod with a footer with type at the bottom. I hope you can see it in the attachment. It is unmistakable on the print.

Thanks in advance.