Problem with monitor display suddenly "distorted"

[goodstuff9]

Ubuntu 18.04.5, gnome shell 3.28.4, x11 x.org 1.19.6

Suddenly, with no changes or reason that I am aware of, when I turn on the computer and then log in to my user account, one of the three monitors (always the same monitor, it has an HDMI connection) displays the ubuntu desktop but it is very distorted. I don't know what other word to use than "distorted". But - What I have stumbled on is that, after the computer has booted up, and I am confronted with this one monitor displaying everything distorted, if I log out of my user, and then log back in to my user, that problem goes away, everything displays beautifully. This happens on only one of the three monitors, and always that same monitor.

I don't know where to start to diagnose what the problem and, and how to fix this.

What should I do to find what is wrong, and how to fix this? Thanks for any help.

[CelticWarrior]

Start by posting hardware specifications, especially graphics.

[goodstuff9]

Thanks.

I am not sure exactly what is helpful. Here is some stuff I found, not sure what any of it means:

CPU is Intel Core i5-4460 CPU @ 3.20 GHz
Motherboard is ASUS Tek H97I-PLUS Rev X.0x
GPU is ASUSTek Computer Inc. Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller [1043:8534]
Kernel is 4.18.0-25-generic
Open GL Renderer is Mesa DRI Intel HD Graphics 460
Open GL version 4.5 Mesa 20.0.8

Does any of this help?