Border around right-click context menu – is this new or just a bug?

Switched back to the old context menu recently using Chris Titus's Windows util. Don't remember seeing a border around it before—is this a native Windows 11 thing now? Looks nice either way.

Edit: It disappears after a restart. Seems to happen when I boot with both TV and monitor connected—output defaults to the TV, and when I switch to the monitor, the border shows up. Probably a scaling-related visual bug, though I have no clue how that affects the context menu. Somehow it does.

Also noticed shortcut icons aren't showing the usual arrow indicator—everything in the screenshot except This PC, Recycle Bin, and folders is a shortcut.

And some Windows-related icons in the context menu look glitched too.