Hover state won't show

Hi, 

I'm finding that hover states won't activate in preview or review when looking at the scene or project (works fine in slide preview). E.g. hovering over a marker should show the text. On first hover nothing happens, then I move away, and back again and it shows. 

This is the simplest instance of this happening. In other hoer interactions, on first hover over a character, nothing happens, (no hover 'hand' shows). then on retry the trigger activates the desired action (text shows), but the character disappears altogether.  Have worked around this one by using layers, but what is the story with the weird hover states not activating? See video attached

Cheers,

Sonya