Sorry to break it to you but it's definitely caused by another addon, most likely the gm_construct 13 beta. Have a look at when that addon was released, when people started reporting these sightings and when this map was last updated.

I saw it too, and I also have gm_construct 13 beta. So I guess that addon is doing things to other common maps to screw with people.

It probably happens in any map that has a nodegraph or navmesh. I doubt it's targeted towards specific maps.

blueberry pie the sky is missing textures

引用自 FREEMANNNNNNNNNNN：

blueberry pie the sky is missing textures

If you're using Life Mod, you need to disable the Uncompressed HDR Textures option under the Textures tab. If that doesn't help, try disabling other addons and restarting the game, or verifying your GMod installation. If you're still having trouble, please make a new thread instead of posting in an unrelated one.

If you want black figures just download the black shadow nextbot

yes but i don't like nextbots

he's not a guy that chase you he show up on corners and dissapear when seen

it could be haunted, something scary happend to me while playing with nextbots. no it wasnt a nextbot, i deleted all nextbots during that sound. that sound sounded like a slowed alarm, and yeah.
no, im not making it up. im not that type of guy that wastes my time on lies.

its just a part of the map ambience,
maybe its taken from half life 2 (that game has some scary ambience)

Again, not haunted. If you run my maps with a clean GMod installation and without any other addons, these things simply don't happen. But feel free to dig through the GMA's contents or the map's source files if you want to look for evidence.

If you check your subscribed items on Steam, you can sort them by when you subscribed to them or when they were last updated. I suggest you go through this list in chronological order and check their comments for similar reports. It's trivial for any addon, no matter how innocent it looks, to break or trigger things in other people's maps. That's part of the reason why I'm no longer interested in creating stuff for GMod.

Quick update on this: I recently spoke to the author of the gm_construct 13 beta addon, and he agreed to remove gm_fork from the list of affected maps (turns out the addon was targeting specific maps after all). This should eliminate most of the sightings that people have reported in this map.