It may not be Occlusion Culling. You may have too many lights in forward rendering mode. Go to Edit → Project Settings → Quality and make sure that your Pixel Light Count is more than the number of lights in your view at any time. Unity automatically turns off the least bright lights to make sure the Pixel Light Count is never exceeded.
It is occlusion culling. I have two point lights in my scene, and Pixel Light Count set to 8.
Turn on Occlusion and the lights die, turn off and they come back. In the editor the scene lighting looks fine, but in game view it’s not. I think there’s a bug with Occlusion and point lights.