Lights Question

Hi. Just to clear something up.
I have an 04 Aprilia SR50 Lc scooter.
Should just one of the front lights come on in the day when light .. then both at night when dark?
What i'm seeing so far is that when i start the engine in the day just the front left light comes on (looking at the light) .. but when i start the engine when its night .. both seem to be coming on.
Is this correct? Or just should both lights be on constantly when the engine is on?

Thanks