Hi folk! Just to set the scene -- I install a metric ton of games as sort of a todo list, and have 4 fences total, one is for game development, one for games I am actively playing, one for "todo" ones (pending), and one for games I just aim to keep installed all the time because they are my favorites. All of the games ones short 5 columns right now, the expected amount. However, sometimes after coming out of a game that has been full screen and resized the desktop, the fences only have 4 columns.
The fix is pretty easy -- unlock my fences, move the border by like one pixel, let it snap back into it's snapped size, and we're back to 5 columns. This does not happen every time so it's hard to say precisely what's causing it -- aside from being 99.9% sure it has to do with a game changing the resolution. I've been trying to keep an eye out for what specific resolutions cause it -- or whether full screen vs borderless makes a difference, but so far I don't have a lot of other useful information to share I'm afraid.
I have never seen this happen on an established game. Meaning one I've played over and over. I'd almost wager it only happens when I launch a game I've never launched before and it tries to decide what the screen size is, or starts with a bad resolution.
I was hoping to have more information before I posted something but alas -- this has been going on for years now -- at least since Fences 4 (I'm on 5 now). So unless y'all have an idea right off the bat, anything I can do to "help me help you"? 
As an aside -- I wish I'd checked out Fences sooner than 4 -- it solved a lot standing issue I'd had in how I organize things. 