Strange overmap reveals after peeking up a z-level

[DragonWizard23]

Describe the bug

My character was exploring a sewer system and decided to peek up a ladder instead of climbing it directly (I suspected there would be several zombies). However, this revealed the surrounding overmap tiles at the sewer z-level, which was unexpected.

Attach save file

2024-03-31-trimmed.tar.gz

Steps to reproduce

1. Enter a sewer
2. Explore the sewer until you reach a ladder
3. Peek up the ladder
4. Check the map to see if it revealed nearby overmap tiles on the sewer z-level.

On this save, this behavior can be replicated by walking north to the next ladder and peeking up.

Expected behavior

I did not expect the sewer level overmap tiles to be revealed because the character has not seen them (they are also solid earth).

Screenshots

Nearby overmap tiles were revealed when peeking up a z-level.

Versions and configuration

• OS: Windows
  • OS Version: 10.0.22631.3447 (23H2)
• Game Version: fa7e258 [64-bit]
• Graphics Version: Tiles
• Game Language: System language []
• Mods loaded: [
  Dark Days Ahead [dda],
  Disable NPC Needs [no_npc_food],
  Portal Storms Ignore NPCs [personal_portal_storms],
  Slowdown Fungal Growth [no_fungal_growth]
  ]

Additional context

This bug does not cause the game to crash.

[Amnestasia]

After conducting a few test, can confirm that theres definitely something wrong with peeking z-levels as a whole, as this doesnt apply solely to sewer systems. The following two clips show my findings, and I imagine it also applies to other z-level switches.

Z-Level.Test.mp4