Descriptive Problem Summary:
If the light is rendered as part of an object that isn't visible to you, the light shouldn't be rendered but it is.

In other words. Unless you're using SEE_BLACKNESS things hidden by opacity shouldn't be visible outside of the opacity. Which means, big lights inside a room that you can't see inside of, shouldn't be leaking through the walls
and as soon as you can see inside the room, then the light should go through the walls.

Here is a demo:
https://easyupload.io/3w8elu

Expected Results:
https://prnt.sc/prsvg4
Actual Results:
https://prnt.sc/prsva8
Does the problem occur:
Every time? Or how often? / It does happen all the time.
In other games? / Probably
In other user accounts? / Yes
On other computers? / Yes

When does the problem NOT occur?

Did the problem NOT occur in any earlier versions? If so, what was the last version that worked? (Visit http://www.byond.com/download/build to download old versions for testing.)

Unknown.

Workarounds:
No workaround