Latitude 5330 - Windows +k and Windows +p not working

Hello

I am ICT-coördinator on a school with about 100 teachers and 1000 students. Each of them has a Dell laptop. Most of our users has a Latitude 3310 2-in-1. Recently, a number of teachers received a Latitude 5330 2-in-1. On a number of these devices, following problem occurs:

-Windows + k and windows + p not working. We use this for casting the screen to a Microsoft Wireless Display Adapter (MWDA).
-Windows for Start menu, windows + s, e, a, i, r, ... works fine.
-I can connect to a MWDA via the settings, but others can't
-The key combinations don 't work with an external keyboard either.
-I removed keyboard from device manager, and reinstalled.
-I tried sfc /scannow
-I treid Dism /Online /Cleanup-Image /RestoreHealth
-I made sure all updates are installed, both Windows and Dell updates
-Reinstall of Windows fixes the issue, but we still don't know what causes it. And we can hardly reset everyone's laptop who encounters this issue.

Anyne knows what causes this, and preferably, how to solve it? I know it might not be a Dell issue, but because we only encounter this on our Latitude 5330 models, I thought maybe someone here might know something. 

Thanks in advance!
Stefan