Duplicants doing low priority errand instead of his job

It happens often. I see it well on my builder/digger :

Look at Travaoldo.

Has you can see, he's job is to build and digg, and attack if needed. But all over errands have low or medium priority.

But even if he was close to the building requests shown in the background, he want to supply sand to a deodorizer at the opposite side of the base ! O_o

There's an issue here.

He's status say he deliver "critical materials". When does the deodorizer became a "critical" building ? O_o

OK, I often set it to priority 9, so that the deodorizer is quickly supplied. But it duplicants can live with some polluted oxygen ... -_-

Metis.sav