DeckLink Mini Recorder vs Magewell ProCapture SDI in OBS

[sjtwmedia]

Good day, I’m having a problem with our DeckLink Mini Recorder in OBS. Using SDI and setting the input to High(OBS)it steals the feed from our Magewell card but if we leave it at 720 then there is no problem. The cameras are both PTZOPtics set for an output of 1080p30, MacPro 5,1 , HS.

Any ideas why this is happening?

Thanks