Inconsistent lighting bakes

Hi,

I have a problem with baked lighting being inconsistent (as mentioned in the title), and I have looked for a similar problem but I couldn’t find one, as it’s a bit too specific.

So I was doing some lighting tests, with results I was quite happy about. I’ve change a few World Settings to increase the quality of the baked lighting, and so I got something like this:

And as you can see from the door, I’ve added some models after baking the light (the test I did at first) so I definitely have to rebake.
I changed nothing with the lighting, I tried removing the models I added, I tried changing the world settings to higher/lower values just in hopes that I’ve missed something, but to no avail.

No matter what I tried, the lighting degraded atrociously to the following:

so basically the walls got darker, and the floor got brighter, now I could tweak the materials to fit the previous contrast, but as you can see the sun’s light will also be darker, and the columns on the left will look too bright.

My scene is simple as far as lighting goes, a bounce card and four spotlights for indirect lighting:

the directional light and sky light are just there to tweak the lighting, and are both movable.
I tried both switching them to static/stationary, and removing them completely. nothing changed.
All walls and columns are BSP, and have a lightmap resolution of 1024 (changing that did nothing as well).

Now I’m just paranoid about saving the scene because I don’t want to lose the first bake, so my progress towards the scene has faced a dead stop.

Any help and/or suggestions would be highly appreciated, thank you.
.

Sorry for the #bump, but it’s rather important and I still cannot fix the issue.
Thanks