iPad Pro 3rd Gen not detected by PC or Mac in recovery mode

Hey everyone! I have a strange issue I wanted to run across the crowd for ideas. I have some iPad Pros 3rd generation that need to be factory reset. The catch is that we've locked them down through MDM, so we can't just perform a erase all settings to factory reset them. (I work for a school system and we've found that it's best not to give the kids access to a self destruct.) So, to factory reset the devices, I typically boot the devices into recovery mode and use Apple Devices to restore the OS back onto the devices. (Yes, I use a PC to typically recover my apple devices - this school district isn't terribly Apple friendly - but I still try to fight the good fight). Finally, I'm not factory resetting the iPads through the MDM because they've been offline for too long and aren't able to be managed any more. (That's why I'm resetting the devices - to get them back under management again.)

The weird thing is that I can't find these particular devices after I get them into recovery mode. On the PC I'm not finding them in device manager. I've even gone on to bring in my personal mac and it seems to be having the same problem. I'm not seeing the device in the finder once it's in recovery mode.

I've tried switching out the cable but I'm still getting the same behavior. Has anyone else seen something like this before?

Thanks!