D735 with 3 D7 expansion modules.....delay when dialing digits on the screen

I have a D735 with 3 D7 expansion modules. A noticeable delay when the phone has a D7 module plugged into it. without the modules, dialing has no delay. I have PoE and the correct power adapter plugged into the second module. Everything works, but the delay when dialing is causing us issues. What is causing this and do i remedy it?20230920_122732_33606319587646.mp4