It seems like mapLightScale in a camera's animation set editor isn't fully zeroing the appropriate global light properties anymore.

This makes the shadows on characters (and everything that's using the "Hero" shader) appear inverted when mapLightScale is low enough. This is a GIF made in dota.vmap, there is just no background because I pulled in farz very close for crisper shadows. I also thought this might have been a material diffuse warp thing at first, but it's not, I checked.

My interpretation of the issue: it looks like it's forgetting to zero out what is marked as "Shadow Scale" in Hammer's ent_dota_lightinfo (not "Shadow Ground Scale", which works properly and affects GlobalLitSimple materials, whereas "Shadow Scale" is for the "Hero" shader—am I getting that right?). Everything else interpolates to zero but this parameter, hence the shadows stay "bright" and look inverted when mapLightScale is set to 0.

Here's a Hammer Map Editor screenshot where I've set all of the Light/Ambient/Shadow values to 0, except the "Shadow Scale" one, and it reproduces the same look of the issue in SFM, so it has got to be the parameter that's not getting touched by the slider properly anymore.

I tried this out in a bunch of maps—my own, Valve's, and some that I haven't touched for two years at this point—but the behaviour is the same every time.

(I'm going on a wild guess here, but I think this might be tied to the new properties in ent_dota_lightinfo. I think you folks have added "Shadow Secondary Color", which allows tinting the "Hero" shadows separately from the "GlobalLitSimple" ones. And there's also "Ambient Shadow Amount", which seems to be controlling how much of the ambient light is allowed in the sunlight's shadow.)

As a side note, I know this issue has been in SFM2 as far back as at least as May 30th, because I went back into my TI7 project back then to do a little joke post and I'd noticed that the lighting was a bit brighter then... I just checked now, and sure enough, those scenes have the mapLightScale slider set to about half... so that joke post was affected by the bug too! Funny how I'm getting answers to a passing "huh" moment, over a month after.

It's not a huge issue to fix compared to, like, the spawning models thing, but, since it's Short Film Contest season, a fix would be nice to have soon