Duplicant Motion Sensor wrong on Oil Refinery

There are lots of buildings that do this. You might want to read about the tile/cell of interest: https://oxygennotincluded.fandom.com/wiki/Cell_of_Interest. Most of the time, it's where the automation port is.

It makes sense for detecting if a duplicant is operating, pro-gamer style (because you only need to check one tile), but it does not make much sense visually. One of those "you just have to know it" mechanics.