Same exact issue here on X1 Lenovo Carbon Gen7 with Integrated Iris 620 graphics.
I tried to get lenovo to resolve this issue but its like talking to brick wall so i ended up making a job in task scheduler that reboots dwm.exe everytime the machine comes back from sleep.
I tried downgrade my drivers using intels official drivers but these won't even install on a lenovo system, it seems lenovo has some custom integration of this chip making only their drivers possible to install which worries me because they don't care about this machine anymore, its year 2018 model, they probably want me to give them another 3000$ for a new laptop rather then updating the driver at this point.