Lightmapping in WebGL much darker

I use Unity 5.5 and bake non-directional lightmaps for the indoor-parts of my WebGL-scene. Those parts are also excluded from my main realtime light-source (Time of Day) via layers. I disable the Time of Day light-source and sky-sphere during baking so it will not interfere with the process and only the many lights I've placed indoors are taken into account. After baking is complete I enable the Time of Day objects again, hide the baking-lights and take a walk through the scene inside the editor... everything looks fine there, the baking is bright and inviting as it should be.

Then I build the scene to webGL and try the same online... the baking is definately there but it is MUCH darker (and consequently looks much less inviting).

Does anybody know what happens there? Why do the results vary? This makes baking pretty unpredictable and hard to grasp.

 

I don't think it's necessarily a bug, maybe I am just overlooking something in regards to lightbaking...

Okay it seems setting the Light-source of Time of Day to Realtime instead of Mixed had it lighten up even those parts of my scene that where Layer-excluded from it via its Culling Mask (which is a bit weird). This only had an effect inside the editor of course since GI doesn't work in WebGL.