UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36

Steps to reproduce the problem:
0. Kubuntu 18.04, KDE as window manager
1. Run chrome, load a web page
2. Set the computer to standby
3. Restart from standby
4. Notice that all visible chrome windows look trashy. Lots of small random blocks.
5. If you click a non-visible table, everything looks normal.

What is the expected behavior?
You expect to see exactly the last state of your browser perfectly.

What went wrong?
Apparently, the windows were not refreshed properly.

Did this work before? N/A 

Chrome version: 68.0.3440.106  Channel: stable
OS Version: Ubuntu 18.04
Flash Version: 

Tried doing this with Firefox, but Firefox comes back OK. Also, I noticed the same problem with a few of the plasmoids, but not all.

Nvidia Geoforce 750 ti, 390 driver (the latest)