Thanks for your reply. I went through the troubleshooting steps, here are the result:
Verify that ALL your icons are represented in the default Fences
Reboot
Q: Are all of your Fences and icons where they should be?
A: No, all of the icons moved to the bottom of the screen.
Create new Fences, move icons to them
Reboot
Q: Are all of your Fences and icons where they should be?
A: No, same issue.
If all is well, plug in 1 (and only 1) additional monitor
Reboot.
Q: Are all of your Fences and icons where they should be?
A: No, same spot. But if I restore the icons, it looks normal. This only works without the 2nd Sceptre F27 monitor plugged in.
If all is well, move some Fences to the newly pugged-in monitor.
Reboot
Q: Are all of your Fences and icons where they should be?
A: Yes
Repeat the monitor additions and Fences placement, rebooting in-between each addition and verifying that their placement is as expected
If any monitor addition has Fences \ icon placement go wrong, detail what one and what the connection type was.
The issue occurs when I plug in monitor 3. It is a Sceptre F27, which is the same model as monitor 1. The other monitor are different models. I can plug in the other monitors and the icons will restore to the correct position, but when plugging in monitor "3" (the 4th monitor in testing) then the icons are bunched up at the bottom.
I'm not sure if this is related to the other monitor being the same model number, or if it's because the monitor position is on top of the existing monitor. Those are the two clues that stand out to me.