The entire MUD works this way. This isn't area specific.

If you had a unique mob for each room wouldn’t it prevent it? It only happens when mobiles are reused? In this scenario and in this area and with the repop timer it seems needful.

That's true MUD-wide too. Nothing here is specific to the area.

A few years back the IMM team asked that mobs that repop and don't go back to the same room they spawn in, but spawn in another mob's room of the same type, be noted so that they could be fixed or standardized.

As example, dark guards from old arial city were a great example. You have rooms in a row that are 9 wide, and you kill the ones on the east of center and when they repop, they don't go to the east rooms, they pile up in the west rooms. I don't recall which IMM but they wanted to be notified when this stuff happens so it can be fixed/standardized.

This was because of the way they were set was to repop them in specific room order, one after another, until the total number for that area was met rather than the intended rooms they were supposed to be in.

This made learning in certain places difficult or impossible if the process went on too long.

This could lead a person who found a situation like this to think it may be a bug or oversight.