Saving Ai File To High Quality PDF Leaves Red Box Surrounding Artwork

Windows 10 64 bit - Ai CC 2019

Each time I save my (CMYK) Ai file as a High Quality print PDF and then preview it in Acrobat DC, I'm seeing this red line surround my artwork. I'm not the most savvy person with Acrobat, so I don't know if this is just something that needs to be turned off or not. I don't see the line while previewing the PDF in Ai. Below is a screenshot of what I see. I'm concerned that my final pdf has to go to a print shop and I certainly don't want this to print.