Start Windows Symbol is Yellow

The START symbol on my Taskbar (Formerly the W7 START Orb) on one of my machines is a bright yellow color. On my other machines it is white.
Changing the color scheme does not change the color of the symbol.

This behavior has been going on since I did the upgrade installation over a year ago, but because it is not a big issue I have been ignoring it. So none of the Windows updates have changed anything.

Any ideas on how to find and correct this?

Personalize > Colors >
Make Start .... transparent = ON
Show color on Start ... = OFF
Show color on title bar = OFF
Choose your app mode = Light

TV2 said:

Any ideas on how to find and correct this?

Personalize > Colors >
Make Start .... transparent = ON
Show color on Start ... = OFF
Show color on title bar = OFF
Choose your app mode = Light

1. Does the color change when you hover the cursor over it? To what color?
2. Does your problem appear in Safe Mode too?
3. Have you tried switching on and off a couple of times absolutely all the switches in the color section, accent color included?
4. Try to toggle on tablet mode, and then toggle it off.
5. Win + X / System / Advanced system settings / Advanced / Performance / Settings / Visual effects - choose a different one

Win10Pro said:

1. Does the color change when you hover the cursor over it? To what color?
2. Does your problem appear in Safe Mode too?
3. Have you tried switching on and off a couple of times absolutely all the switches in the color section, accent color included?
4. Try to toggle on tablet mode, and then toggle it off.
5. Win + X / System / Advanced system settings / Advanced / Performance / Settings / Visual effects - choose a different one

Note: There is a square yellow box in the upper left corner of my display. I have my taskbar on the top. If I drag it to the bottom, the Start icon goes with it and it is white. The square yellow box remains top left.
This may be a display problem.

1: Hover makes a shaded square box, but it is still yellow.
2: Safe Mode: the yellow box is still there. In safe mode the taskbar is at the bottom. This is how I noticed it was a separate issue.
3: Tried that - no change
4: Tried that - no change
5: Tried all the options, including Custom - no change

Yep. Sorry folks, my bad. It is a display/monitor problem.
I ran Ubuntu and the yellow box persists there too.