Linux - cursor doesn't update until click (bug?)

Distro: Ubuntu 16.04 LTS.

In my game, the hardware cursor updates automatically when the player hovers over particular objects. This works as expected on Mac and Windows. But on Linux, it doesn’t change until I click with the mouse.

I’ve managed to recreate this in a default project (FPS template). On an actor in the game world I have the following tick graph:

Now, this means that on Windows and Mac, the cursor automatically changes to a hand when (and only when) it hovers over one of the movable boxes in the scene:

But on Linux, as I say, there is no change until I click with the mouse. It seems like a bug, but I’m also wondering if there’s a work-around. Maybe some low-overhead code I could call after each change of cursor image?