My static lights won't show

Hi everybody,

I have a problem with static lights in my map, they don’t appear… I’ve read a bunch of forums and seen a bunch of tutorials and I’ve set up things correctly. I even tried in a different scene and I can put up static lightning (on the same objects I have in my broken scene even).
Is there a map-related setting I’ve broken without knowing ? Otherwise is it a known bug (I’ve not found trace of it on forums) ?

Thank you for your help in advance !