Perpetually Collapsing Roof

Game version:
10797

Operating system:
Win10

Tiles or curses:
Tiles

Mods active:
"dda",
"aftershock",
"no_npc_food",
"crt_expansion",
"alt_map_key",
"crazy_cataclysm",
"MMA",
"Graphical_Overmap",
"sees_player_hitbutton",
"sees_player_retro",
"fuji_mpp",
"speedydex",
"stats_through_kills",
"StatsThroughSkills"

### Expected behavior
Roof section collapses normally 1 time per tile

### Actual behavior
Roof perpetually collapsing all the time for days

### Steps to reproduce the behavior
Load attached save file
Remove earplugs (and turn down audio if you have a collapsing sound effect in your soundpack)
Move to the southwest apartment
Observe
Move down a few more floors and continue to observe
[Mega City 3.zip](https://github.com/CleverRaven/Cataclysm-DDA/files/4853679/Mega.City.3.zip)

Alternatively:
Enter an apartment tower (or similar multi-z structure)
Spawn a shock husk or similar on the ground floor
Get them to destroy several several walls
Observe

Start by loading the attached Mega City 3.zip save, removing earplugs, and following the apartment-tower reproduction steps. Compare the expected one-collapse-per-tile behavior with the repeated collapses after walls are destroyed by a shock husk. Done means roof sections stop collapsing after their initial collapse, including in multi-level apartment towers.

Written by the indexing model from the issue text.