The entry chamber for the Fort Ludios level would be completely lit
except for one corner wall if you arrived carrying a lit candle. The
unlit spot turns out to be correct, it is beyond candle radius, but
spots further away than that were showing up lit. That's due to them
bordering a lit region on the opposite side and lit regions seem to
be bigger than their specified dimensions.
I tried to make the lit walls be unlit but it wasn't working. (Making
the lit region be smaller would probably work but might have unintended
consequences when populating the zoo room. I didn't try that.) This
makes the unlit corner show up if light hits the spot next to it, so
that it behaves like the other lit walls surrounding that entry area.
I haven't marked the bug report closed because I don't think this is
the proper way to fix this.