Border added to Dac-70

Has anybody come across this before. I was attempting to split a signal from a MacPro to an ATEM Mini Extreme Pro and a client monitor. Ran into HDCP from the splitter, so I put the MacPro signal into a Dac-70, then into the splitter. Took care of the HDCP but now the signal has a black border. I took out the splitter and just ran the Dac-70 straight into the switcher, same problem.

When I plug in the laptop straight into the switcher, no border. It seems to only be coming from the Dac-70 and the Mac because when I plug a PC into the Dac-70, no border.

Any thoughts, ideas or suggestions are very welcome!

Todd