Qizu

i'd finally say the timer is coded to 1 hour and sometimes the chunk goes inactive so it just takes more than 1 hour but nothing is sure without code

do npcs keep chunks loaded?

That is a good question... someone please test if npc's keep the chunk loaded.
And I think 1 hour isn't too long considering some freaks break in late at night IRL and could easily camp the 1 hour so jammed doors seem fine.

I do wonder, does it work the same with broken doors?
If 1 hour passes will the
"The door was left ajar" go away?