Is it a bug that more locations have their content back later when coming back?

Things respawn in this game.

What is the timer you're asking? Yes, things do respawn, however, it's supposed to be 30 days in game at the longest. There is a current system wide bug where random areas will see items respawn within seconds of taking them, walking far enough away, and coming back to that area.

Well seems like at the disposal ground it is possible to just go get circuitry boards really often. At least before robot was killed. Don't know about later.

Respawning that quickly would be considered a bug, yes.