[SOLVED] Monster activates despite no LOS in ZDoom

I'm working on a vanilla map which I'm testing in ZDoom (2.6.0 to be specific) as well as vanilla because I know how much ZDoom hates vanilla hackery, and I've hit upon a very strange bug: a Cacodemon activates immediately upon starting the map, despite having no line of sight to the player, as it's on the other side of a closed door around a corner of a solid wall (needless to say, this doesn't happen in vanilla). Oddly, it's just the one Cacodemon that's affected; the other monsters in the area correctly don't activate until they can see or hear the player.

Here's the map (it's only a few rooms so far): www.freewebs.com/foxpup/anomaly.zip The Cacodemon in question is Thing 63 and only appears on easy skill. What on Earth has gone wrong?

UPDATE: I've added more geometry to the map, and the problem went away. I'm leaving the original map up, though, because I'd still like to know what the problem actually was. I don't like weird bugs when I don't know what's causing them.

I haven't looked at the map, so this is a stab in the dark, but did you join sectors, by any chance? I recall having an issue where you could wake up every monster on the inside of a building, entirely closed to the outside world, from said outside world. Turns out the problem was the sectors I'd used to define the windows; because the heights were the same inside and out, I'd joined the sectors up, and thus the sound was traveling through the undefined space inbetween the inner window and the outer window and into the building.

Long and short of it, if your sound can reach a sector from where you are, without having to cross two "Block Sound" linedefs, then that sound will emanate from wherever else that sector is, even if it's on the complete opposite side of the map, or completely disconnected from the rest of the level entirely.

It's just some nodebuilder imperfection if I understand correctly. Happened to me several times: some monster would see me through like 30 walls, then I would edit the geometry a bit and the problem would disappear. I don't think you can't do much to avoid this. Well, maybe using very simple wolfenstein-like level geometry can help. :P

And I guess it happens only in ZDoom because it rebuilds the nodes for its own needs or something.

Here is my old thread about this: http://www.doomworld.com/vb/doom-editing/60904-telepathic-shotgunner/

ZDoom by default only rebuilds nodes if it actually needs to. This means that either the map's nodes are fucked up and fail the sanity checks so ZDoom goes "what a mess, let's rebuild those instead" or you have turned on the option to make ZDoom always rebuild nodes.

Or the textured automap is on and the map doesn't have GL nodes.

Aren't the original nodes still used for gameplay anyway, though? Or is the distinction between rendering nodes and gameplay nodes done only in GZDoom?

Haven't looked, but if GZDoom does it I assume ZDoom does as well. Still, in my opinion, worth noting for completeness.

Let's not forget thst ZDoom doesn't use the nodes for sight checking. Maybe the blockmap has some issues?

Memfis said:

It's just some nodebuilder imperfection if I understand correctly. Happened to me several times: some monster would see me through like 30 walls, then I would edit the geometry a bit and the problem would disappear. I don't think you can't do much to avoid this. Well, maybe using very simple wolfenstein-like level geometry can help. :P

And I guess it happens only in ZDoom because it rebuilds the nodes for its own needs or something.

Here is my old thread about this: http://www.doomworld.com/vb/doom-editing/60904-telepathic-shotgunner/

Of course! The sleeping sergeant. Linedef 36 appears to be the culprit in my case. I never thought of that because my nodes work okay with vanilla and in any case I thought for sure that ZDoom had fixed that bug. Guess not.