Touch Bar display partly not working

There are a couple processes that send data back and forth and this is a sign you need you log out of the user account so that those processes can exit and then when you log in, see if the connection is fixed.

Unless this is something that you run into very often, I'd log out and then restart to be sure it's not systemic before expending a lot if time digging into this.

In my case, the 2 Inch length of the right-hand part of the touchbar stopped displaying, but the touch was working from Mar 05, 2020.

Fortunately, on Oct 03, 2020 it miraculously reappeared. Now, only half-a cm of the touchbar is still black. I hope it also comes back soon.