I'd like to add to this - on April 1st I left my computer with icons 'normally' spaced ... on the 2nd I was booting my computer up and I am seeing the desktop now 'completely off' due to the icon spacing having changed. Restoring to an older screenshot does not work as the fences are sized correctly but the icons now require way more space inside. I have not made any adjustments to either fences or the Theme or any other Display setting.
OS: Windows 10 Pro 20H2 19042.868
Icon Size: Medium
I saved the two screenshots (before and after) should you want to take a look at it.
I am using Fences since around the first version in 2009 and I am 100% certain I have never seen anything like this before