iMac 2018 with disturbed screen

[vanrumst]

I have the following problem

iMac 21,5" 2018 model

from time to time the screen can be very strange (see picture).
(most of the time after coming out of sleepmode).

When I click with the mouse/keyboard the strange screen is gone.
It's not a screensaver or something like that.

Possible that I don't see it 2 weeks, but then possible everyday once.

I've contacted the company where I bought it, they scanned the device, tested it 5 days, but didn't found anything weird/strange.

Has anyone an idea what the probleme may be?

nvramreset/smc reset allready done
OSX is Mojave.
No usb devices connected, just wifi en bluetooth mouse and keyboard.

 

[curmudgeonette]

from time to time the screen can be very strange (see picture).
(most of the time after coming out of sleepmode).

Do you have any image processing software installed? Anything from Adobe?

I'm asking because several years ago during the 24 to 30 bit color transition, Apple had some bugs in the graphics stack. It would forget which bit depth was being used to store an image. Using certain non-Apple software exposed the bug.

 

[vanrumst]

Do you have any image processing software installed? Anything from Adobe?

I'm asking because several years ago during the 24 to 30 bit color transition, Apple had some bugs in the graphics stack. It would forget which bit depth was being used to store an image. Using certain non-Apple software exposed the bug.

Hello,
Photoshop & adobe bridge is installed.

 

[vanrumst]

I updated the adobe progs but still the same problem.
Any tips & tricks to avoid this ?