Loss of keyboard/trackpad events

I have a keyboard and Magic Trackpad 2, plugged into a Cinema Display via USB cables. The monitor's DisplayPort cable is then plugged into a MBP/Mac mini. The issue is that occasionally key presses and trackpad taps don't register. Has anyone else experienced this? EDIT: The Cinema Display uses a Mini DisplayPort cable, so I'm using an adapter to plug into the USB-C port of the MBP/Mac mini. Maybe that's the issue?